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FAQs about Circulation Rates for Marine Systems

Related Articles: Circulation, Inexpensive Wavemaker Impressions, by Steven Pro, Plumbing Marine Systems, Holes & Drilling, Plumbing Return Manifolds, Aeration, Water Flow, How Much is Enough, Powerhead Impressions by Steven Pro, Marine System ComponentsRefugiums, Central FiltrationFlow-through Live-holding Systems, Refugiums, Business Set-Up

Related FAQs: Marine Circulation 1, Marine Circulation 2, Marine Circulation 3, Marine Circulation 4, Marine Circulation 5, Marine Circulation 6, Marine Circulation 7, Marine Circulation 8, Marine Circulation 9, & FAQs on Circulation: Rationale, Designs, Pumps, Plumbing, Troubleshooting/Repair, & AerationPumps, PlumbingMake Up Water Systems, Sumps RefugiumsGear Selection for Circulation, Pump ProblemsSurge Devices

How Much? Vigorous (rarely is there too much... 10-20X+ isn't excessive for most settings), chaotic/non-linear... Can come from internal and/or external pumping

Saltwater questions; reef circulation     3/23/17
<Hi there>
I had a 110 gal saltwater a few years ago but moved so sold it. I have a couple of 125 gal freshwater tanks now but the saltwater pulled on me until I got a small one. It is a 25 gal Innovative Marine. It is 7 weeks old. I
recently bought a wave maker wanting to make the tank realistic to the ocean. I just don't know for sure if it was the best for the tank or not and wanted someone else's opinion that I respect. Here is a video of it (Link: Video wave maker). I have it on the lowest setting there is. Thanks so much!
<Your animals look healthy; not too tossed about by current. I WOULD move the Goniopora and mushroom further apart though... to avoid them fighting/allelopathy. Bob Fenner>

Questions about Sumps and glass tank seams and chips      10/11/16
Dear WWM Crew,
<Hit it Eddie>
It’s me again, and I have a lot more questions to ask you. The test fill went great. The tank and the stand did fine. I’m still working on the siding for the stand, so in the meantime, I’m trying to finalize my filtration plans. The plan all along has been to have a sump and a refugium/DSB, but I had to wait until the stand was built so I could know exactly how much room I would have.
<I see>
The 75 gallon tank has the typical overflow with the 1” drain and ¾” return.
<Ugh; a one-inch through-put is too small... DO plan on doing most all your water (re)circulation inside the main tank... with submersible pumps, powerheads...>
However, I intend to use both holes for drains and run the return over the back of the tank.
<Mmm; well, the 3/4 inch won't do much good. See HERE:
The plan is for the drains to empty into the skimmer chamber of the sump.
<Mmm... better later... in a chamber that has about constant level>

The skimmer is an Aqua C EV-180. Then there will be the typical baffles to the other chamber of the sump that will have the return pump. Also in this chamber will be a power head that will pump water to the DSB/Refugium, and the water will then gravity feed from there back to the return pump chamber of the sump. That’s the general plan. Now to the specifics and the questions . . .
I have had a difficult time finding two containers that will fit together in the stand to use for the sump and the DSB/Refugium. I know I can use either smaller tanks or plastic storage containers. For cost reasons the plan was to use storage containers (trying to do this on a budget), but I can’t seem to find the right size.
<Mmm; even online? Container Store, Amazon...?>
Then, a couple of weeks ago, I went by a LFS in a nearby city (hour and a half away) that was going out of business. They had a stack of 20 gallon glass display tanks that they were selling for $5 each. They were each drilled with a 1” bulkhead about ¾ of the way up the back, and were painted blue on all three sides. Because they were so inexpensive, I picked one up, thinking it might work really well for the DSB/Refugium—since it was already drilled I thought I could use this throughput for the gravity feed back to the sump. I took it home and put it in the stand and measured the remaining space for the sump.
Then I made a vain search for a plastic container that would fit with the 20 gallon tank, but couldn’t find one. That left me limited to using a 10 gallon aquarium for the sump.
<Too small; I'd use the 20 for the sump, the ten for the 'fuge>

(The space is too small for a 20 Gallon. Is there a common 15 gallon size? I’ve never seen one.)
<Oh yes; 24" X 12" X 12" if memory serves>
I happened to have an old 10 gallon that might work (see below), and if it doesn’t they are not expensive. So the plan is now to put baffles in the 10 gallon dividing it into two chambers. The water drains into the skimmer chamber and flows through the baffles to the return chamber. In the return chamber are two pumps—the Mag 7 pump
May well overdrive your over-flows.... Again... I would NOT drive this much water through.... IF one of the too-puny overflows becomes occluded... water on the floor>
which will return the water to the display, and a power head which will pump water to the 20 gallon DSB/refugium. From there the water will gravity feed to the return chamber through the 1” drain. To make this work I will have to build a platform to elevate the 20 gallon tank several inches, but I have plenty of vertical room in the stand.
So, now here are the issues/questions:
1. I am test filling the 20 gallon tank, and there are some bubbles in the seams (see pictures
—these are from the two front corners. The back corners also have bubbles, but not quite as many). I have no idea how old the tank is or how long it was used as a sales tank by the LFS. In my purpose it will not be full at any time—only up to the drain, so about ¾ full—but it will contain a 5” DSB and perhaps some live rock. In your estimation is it safe to use for this purpose? I can continue to test fill for as long as necessary. Also, in test filling it I have filled it over the bulkhead (by turning the elbow fittings up I have filled it a couple of inches higher than it will be in normal use). So it has a couple of inches more water in it now than it will have normally.
<I wouldn't be concerned w/ these air bubbles>
2. If the 20 gallon tank is safe to use, what GPH should I look for in the power head to feed the water to it?
<Small; as in 3-4 turns per hour>
3. In regard to the idea to use a 10 gallon tank for the sump, will this be large enough to handle the amount of flow and excess water in a power loss?
<Not likely NO. For SURE you want to "test" here... FILL the tanks up, turn on the pump/s and then turn them off... see how much water "runs down hill", MARK the sump as to MAXIMUM depth (with a permanent marker, tape) and DO NOT fill it any more than this>

I know the 1/3 display tank size rule for sumps, but I am counting the 20 gallon DSB/Refugium too, so that puts me at 30 Gallons.
<Mate; ALL the water above the overflow of the main tank PLUS refugium will have to be accommodated in the SUMP. USE the twenty or keep looking. You've configured a disaster in the making here>
Also, I am going to put a valve on the return line so that I can throttle back the return pump if necessary.
<Not a good idea really. Just get/use the size (pressure, flow) pump that will be on full all the time>
Most circulation will be accomplished through circulation power heads in the display.
<Ah, good>
4. If a 10 gallon tank will work, how much minimum space needs to be between the baffles?
<About... Oh, see this below. Yes to gaps that allow getting a siphon, cleaning tools into>
I did a WWM search and found somewhere that someone put 1.5” to 2” between baffles. To fit the skimmer in the sump I need less than 3” between the baffles, but the EV-180 can be put outside the sump if necessary. I have space behind the sump, just not lengthwise.
<I'd place this IN the sump for sure>
5. Finally, the 10 gallon tank I have has a small chip in the glass (see picture). It is a seashell shape with no cracks, but it is at the very bottom of front panel on the edge. Under normal operation, it will be half-full or so. Is it safe to use for this purpose, or should I pick up another 10 gallon tank?
<I'd at least fill in the chipped area with Silastic. Won't help strength-wise, but will save someone from a nasty cut>
Thank you SO MUCH for continually answering my questions. I don’t want to be a pest, but I don’t really have many other people to ask for advice.
<We're happy to assist your efforts>
I live in a small South Alabama town, and I know of no one else here who is into saltwater aquaria.
<Perhaps a posting on CraigsList? Starting a "Meet Up" group in your area....? Easy, fun to do>
I have a friend who owns a LFS, but he is almost 2 hours away. I trust your judgment. I have CMA and have read it twice. I read WWM FAQs constantly. Yet often my questions are so specific I feel I need to consult the experts. I just hope that it’s not TOO often.
Thanks again,
<Welcome. Bob Fenner>

water flow, SW      5/4/13
I have read a lot on your site. But haven't noticed the use of a "spray bar" for defusing the water being returned to DT from the sump.
<Mmm, consider passé', and folks instead employ fewer nozzles to direct and accelerate the return water flow nowayears>
 I currently have 2- 3/4 pipes about 32" long with 6- 1/4" holes drilled in each section. I have these pipes at the back of the tank on the water line.
These holes aim at varying heights from 2/3 down to 2/3 up at the front side of the tank. I am not sure of the flow amount but I have it set so the 2 - 3/4" pipes in the overflow boxes are maxed out. If I divert more water to DT from pump the DT will overflow.
<Mmm, well... you may well want (to consider getting) a smaller pump... cheaper to run... Use power heads, submersible pumps in the tank itself for real circulation there>
  My questions being.. does this seem like enough water movement for reef system.
<Can't really tell w/ the data provided, but most likely not... That is, you could use more flow>
Is that too much of directional movement or could it be beneficial to adjust the spray bars so some holes are aimed to front, some from ends to middle, and some from middle to ends?
It does seem to be somewhat turbulent now because things seem to wave not just blow one way. The water seems to roll. I would like to get enough water movement without adding power heads . Does that seem possible?
<Not likely nor desirable... Read here: http://www.wetwebmedia.com/marsetupindex2.htm
scroll down to the Circulation, Pumps... tray>
  So much of what I'm reading says once I go to a DSB current can stir up sand a lot. My existing flow now doesn't appear to me like that would be a problem( hence my concern for low water movement).  Also you referred to low ORP as possible reason for small Chaeto growth .
 What is ORP mean ?
<Oh! Oxidation Reduction Potential... see WWM re this string... a VERY useful measure of the suitability of an environment to sustain life>
Thanks again.
PS If you ever think about doing house calls in Iowa I will be sure to get you my address .
<Heeeee! I retired from (very) active service in the trade in 94... but do still get around... mainly to give pitches/presentations at hobby, business and scientific get togethers in the ornamental and aquatic protein production interests; so one never knows. Cheers, Bob Fenner>

Re: lighting, pumping, and new tanks oh my! James! LED input please. Now flow/circ. rate in sm. SW   5/3/13
Hey Mr. Fenner,
<Hey Eli>
Once again thanks for all the input, it was greatly appreciated and James did an awesome job at answering all my questions and more!
<Ah good>
Since then I have decided to go in a much smaller direction I'll be going away for school soon and bringing that large of a system with me would be impossible unfortunately. So while that behemoth is in storage I decided to purchase 29gallon biocube hqi system, I have kept everything stock except for the bioballs which I have switched out to make a small fuge. So my question is about water flow. Currently I have the stock return pump, a 250gph Aqueon powerhead which faces against the back wall of the tank to help prevent detritus buildup and another powerhead that was given to me and I'm not sure it's power but it's probably equal to or less than the Aqueon. From what I've read the more flow the better
<Up to a point>
I just want to make sure my inhabitants aren't living against the glass!
<Ah yes>
They seem to be ok one have a percula clownfish, one blue green Chromis and one fire fish. As far as corals go I have two stalks of pulsing Xenia, a few Zoas and a small patch of green star polyps. So do you think it's to strong of flow for them, or could possibly be too strong for corals in the future?
<Might be. The only real way to tell is to set up and fire all over>
 I have about 50lbs of live rock. Here's a photo of the setup Thanks again for your input
Eli Ramos
<And you, Bob Fenner>

SW, circ. SPS sys.      3/1/13
Thank you for the many answers.
I will do as you instructed.
Now I am reading about the circulation of the water and the flow. I have read many different articles and opinions even at WWM and they suggest from 40 times the Litres of the tank to 60 times. What do you suggest. My SPS tank will be approx. 120 Litres and I also want to arrange the flow at one of my other tanks that it is 450 L. How many pumps do you suggest for each one of these 2 tanks and how many litres per pump.
<Two pumps are better than one...>
Thank you again for your precious info and of course your time.
Best regards
<And you, BobF>
Re: Help Needed!!     3/1/13

Thank you again for your answer. So 2 of them , but to your opinion how much
power should they have?? How many times the litres of the tank??
<This is gone over on WWM... a few tens of turnovers per hour, non-linear... B>
Best regards

water flow is there a limit    2/6/13
Hello Crew,
Previously I had a 90 gallon bowfront with around 2,400 GPH circulation. I now have a 150 gallon saltwater tank. In this tank I am hosting several fish: Blue Regal Tang, Yellow Tang, Niger Trigger, Dog Face Puffer, 4 Green Chromis, 3 Yellow Tail Damsels, a Sailfin Tang, and 3 Tomato Clowns.
<... this is way too much life in such a small volume... You need twice plus this volume>
 Inverts are several crabs and snails, a chocolate chip sea star, and a pencil urchin. Corals are as follows: Pink Birds Nest, Red Monti cap, Green Mushrooms, Green Star Polyps. My tank parameters are nitrates= undetectable, nitrite= undetectable, ammonia= undetectable, phosphate= I am unsure at the moment as I am out of tests. I have kind of heard and read multiple views on flow and circulation. My current setup has 6 Sicce Voyager 4s rated at 1,600 GPH and 2 Sicce HP 4000's rated at 4,000 GPH.
This puts me at 17,600 GPH and is without including my 1,400gph return pump. This puts me at around 117x turnover rate. I have lost some mushrooms and the remaining ones now stay really retracted. Also my birds nest polyps do not extend, however my GSP is well extended every day.
<It (the polyps) may be outcompeting the other Cnidarians here. See WWM re GSP compatibility (the FAQs)>
My power heads are not pointing directly at any of my corals.
Do you think I have to <too> much flow in my tank should I lighten up a bit maybe go down to just the 2 large Sicces and be at 8,000 GPH?
<Yes I would... this should be sufficient flow>
Would just like an opinion if you have any thoughts. Thanks.
<The larger system... You need it, now. Bob Fenner>
Re: water flow is there a limit    2/6/13

Do you really think I need  a larger tank? My tank Dimensions are 72x26x18  LXHXW.
<Ah, sorry re... not enough cafe this AM... I skipped over your msg. and thought this was still your 90 gal.>
I feel as if everyone has a lot of swimming room and hiding places. When looking at the tank I would of never guessed it to be cramped at all. I know more plays into effect then that suck as territories and what not. Are you saying I should go for a 280 or something even larger?
<Perhaps in the future; with growth, additions to your livestock. Cheers, Bob Fenner>

Re: Nano action plan, pb  7/10/12
Great thanks so much for the reply, 1" returns it is, bet you saved me a flood.
<Ah, welcome>
I've built the two tanks (beveled glass worth the extra $ IMO) stand and plumbing, now in the testing phase.
I was aiming for about 600 g/hr for my 20g, but unfortunately flow is down to 400 g/hr after 4 foot head loss, plumbing & 3/4" scwd.
<This should be plenty>

For anyone looking at a scwd as a cheaper alternative to an Ocean Motion 4 way be aware while one output is going the other still runs at 10-20%.
Return is plumbed like this 560 gallon Pond pump (7 ft max head) - 3/4" flex pc - 1" to 3/4" Hanson nut and tail bulkhead fitting - 1" bulkhead - 1" pvc riser - 3/4" soft plumbing (surprisingly watertight, glued & siliconed just in case) - scwd - 3/4 soft pvc
Can I use eductor to ramp the flow of my pond pump back up closer to the 600g/hr mark?
<I wouldn't. Not needed and too much chance of damaging life on the intake>
I looked on WWM and saw they can be used with non pressure rated pumps, but I'm not sure if the back pressure would effect the scwd.
<Not a good idea there either; though the difference (in pressure) is nomi-mini-mal>
Also would I want the 3/4 inch or 1/2 eductor?
Nick Surgeon

Too Much Flow For Fish In Reef/Water Flow 1/11/12
Hello there,
<Hi Justin>
 I have had a 75 gallon reef up and running for about three years now and just started upgrading some of my outdated equipment.  I have read numerous articles about water flow and it has always made me feel that my sump return (powered by a quiet one 3000 at a vertical rise of about 6 feet) and my old powerhead (rated 450 gph) crossing the tank to interfear <interfere> with the sump return were insufficient.  My livestock (corals and fish both) have always fared well with a few hiccups along the way, but brown growth upon the sandbed angered me.
<What is your nitrate level, are you using a protein skimmer?>
I thought that a little more water turbulence may help to solve the problem although I know there are other solutions I felt it was time to replace the old powerhead that I have been using since I started with a FOWLR tank 5 years ago.   With some Christmas money I went ahead and decided to upgrade/renew my equipment and purchased two Hydor koriala <Koralia> 550s. 
From what I have read they were not really as much as a reef should have but more flow thatn <?> that really scared me to be honest.  They arrived today and I immediately removed my old 450 gph powerhead and replaced it with the two Hydors.  I placed one of the powerheads on the opposite end of the sump return pointed toward the opposite top corner of the aquarium. I placed the second Hydor on the same end as the sump return.  I placed it low in the aquarium and angled it to flow the water along the back and towards the surface of the aquarium (this is a place I felt was previously untouched by good circulation in my tank). Right away I could see that the water flow was significantly more turbulent by the way my fish appeared to struggle.  I questioned if it was too much but have read many times that it is nearly impossible to have too much.  While wathcing <watching> some football tonight I glanced over at my tank to see a horrible sight.  My beloved flame angel was being tossed around like a ragdoll.  I rushed to the tank and shut down the powerheads.  The angel's breathing was erratic and I am sure it will be gone by the morning as it simply lie on the floor of the tank sporadically making an effort to get started. Could too much water flow have caused the death of a long time healthy fish.  Could this have been too much flow for the strength of the fish and have cause death by exhaustion in just a few short hours?
<Unlikely that the pumps were the direct cause and your new pumps are not overkill.  I've got around 1500gph on a 65 gallon system. With propeller type pumps it is not necessary to place near the bottom or is it desired for the reasons you state.  Propeller pumps produce a wide angle of flow and placing near the surface will provide plenty of water movement near the substrate.  You may want to use the rest of your Christmas money and buy the Koralia Wavemaker that can be used with these pumps.  This will provide random flow patterns which break up the flow pattern.  See here. 
Or have I misread and misunderstood what is appropriate for the water circulation in my tank.
<May want to read here.  http://www.wetwebmedia.com/circmarart.htm>
<You're welcome.  James (Salty Dog)>

Needle wheel vs. paddle impeller   8/9/11
Hi, I had a question about needle wheel impeller vs. paddlewheel impellers.
I have a used Rio 2100 and it came with a needle wheel impeller. The Rio 2100 is rated at 700gph. I hooked it up in my sump tank for my 55gallon corner saltwater aquarium. From the sump to the top of the tank is about 5 feet and I am hardly getting any flow from the returning water pipes into the tank. Does the needle wheel drop the GPH of the pump by a lot?
<Oh yes indeed... the needle wheel is intended for mixed air and water venturi use... NOT for water movement. Won't move nearly as much volume, nor pressure.>
Should I buy a new paddlewheel impeller, Or do I need a stronger pump?
<The former>
Orange County Cali
<Welcome. Bob Fenner, San Diego currently>

Open Loops & Closed Loops (Flow Rates) -- 07/23/11
Hello to the Crew,
<<Hiya Daniel>>
I was just struck by a thunderbolt when I realized that the sump flow rate (filtration, open loop) should be vastly different than the in display circulation (closed-loop system).
<<An epiphany, eh>>
Given that I have a display tank that's 175g and a total system volume of 380g (all before displacement), do I have the following correct:
Open Loop (sump filtration): To be 3-5 times display volume. Hence, 525g to 875g should pass through the sump filtration system.
<<This is likely fine'¦as long as there are no issues with noise, excessive bubbles, etc. With ancillary filtration equipment located in the sump, I find the longer dwell time of the slower flow rates to be beneficial>>
Closed-Loop (in display circulation): For reef tanks containing SPS, 20-40 times display volume. Hence, 3,500gph to 7,000gph.
<<This depends largely on the 'type' of flow provided. With the right flow type/method, it's hard to provide 'too much' for almost any species. I very much suggest you research 'gyre' type flow>>
If I have the above correct, my Reeflo Dart, acting as the system's main pump, has been pushing water through the open loop way too fast (in theory).
<<Controversial'¦ But yes, I would agree here>>
Only reason I care at this point is I'm turning my fish-only system into a reef system, and I'm striving for optimal filtration and circulation
<<What you propose is beneficial to both systems>>
(now realizing they are not necessarily inter-related, perhaps?).
<<Mmm'¦ Related perhaps (and equally important)'¦but different, yes>>
Thank you very much for your time,
<<A pleasure to share'¦ EricR>>

55g Tank Water Flow 3/22/2011
<Hello Guy>
I been reading a lot on your site (and others) regarding water flow and am still not sure about whether or not I have too much in my tank.
We have a 55 gallon tank (approximately 50 gallons of water after all the live rock and sand).
I have a Rena Filstar XP3 (450gph), a CPR Aero Force Skimmer (70gph) and two Hydor Koralia Evolution 750 pumps (750gph/each). This is way out there considering the 10-20 times flow rule I have seen on your site, but many of your FAQs seem to indicate that higher can be good too. I have even read elsewhere that 20-40 times is desirable. Can you please help me understand how much is too much and if I am doing well or not for my tank?
<Will all depend on the animals you keep. Some like strong flow, some like moderate, etc. Searching your animals on WWM should help you here. As a general rule, at least 10X the tank volume.>
We started with on one Koralia Evolution 750 pump but felt we could benefit from having one at each end of the tank to make it more turbulent on the other side and create a more random water flow, so we bought another one.
There is definitely better surface movement on the one side that there was. And I don't know if I just haven't noticed this before, but since adding the second pump I have seen our peppermint shrimp scavenging on the wall and the skimmer outtake -- she seems quite 'happy'.
There is a Bubble Tip Anemone whose tentacles are certainly swaying a lot more in the flow - could it be too much?
<Likely so if it were laminar flow, but the Koralia pumps spread the water over a large area avoiding any jet streaming effect. Anemones and corals seem to do much better with
alternating flow produced by the use of a Wavemaker. Have you read here and related articles/FAQs found in the header? http://www.wetwebmedia.com/circmarart.htm>
Thank you for your help,
<You're welcome. James (Salty Dog)>

Powerhead Too Powerful?/Water Flow 11/1/10
Hello Crew,
<Hi Dave>
Since I found your website you have basically walked me through my whole aquarium process so I thank you for that.
<You're welcome.>
I am happy to report that my cycle completed and after getting my parameters where I wanted I finally got my first fish. My girlfriend and I picked out a pair of Ocellaris Clownfish (one black and white, one orange) from Premium Aquatics.
<A reputable store/etailer. Is where I do business.>
The fish made the decision easy for us as they came to the front of the tank to greet us while the others hid in the back.
<Ah, the hungry ones.>
The worry I have is that they are both under an inch long and I think my Koralia #4 may be too much for them. They look like they are working pretty hard except for when they hide in the corners of the tank. I assume they found a bit of a calm zone there. I made the mistake of shutting off the powerhead and it almost cost the fish their lives. I found them pail
and sluggish in the corner, but revived them by turning on the head and giving them a little push. Color and activity promptly returned, but I am afraid I am going to kill them by exhaustion. I also have a 4 inch sugar fine sand bed to consider that the 4s blew all over the place. I was thinking about going down to a pair of #2s, or one #3. Which would you recommend? Or would you go another way entirely?
<Pretty tough for me to visualize/answer without knowing your tank size both in gallons and dimensions, but if you are kicking up sand, the flow is likely greater than necessary. You may want to try pointing the powerhead toward the surface and see if that calms things down a bit. If not, I would suggest using lower flow rate powerheads. A total of 10x the tank volume in flow rate is what I would shoot for. I prefer the use of wavemakers which change flow direction on a timed basis. Talk to Jeremy at Premium Aquatics, he is very knowledgeable in this regard and can recommend a suitable wavemaking system for your tank if you should decide to go this route.>
Can't thank you enough for the site and all the help you give me.
<You're welcome. James (Salty Dog)>
Re Powerhead Too Powerful?/Water Flow 11/1/10
Hello again James,
<Hi Dave>
Sorry about the omission. It's a standard 75 gallon. 48 x 18 x 21. It has a Remora Pro w/Mag 350 and a Marineland HOT Magnum (both your recommendations). I am only using one of the powerheads, but no matter what direction I point it, it's too much. The sand isn't a problem but the fish look like they are in a constant fight.
<In my opinion, two Koralia 4s are a bit much for this tank.>
I will get in touch with Jeremy. I was thinking that two #2s (750 gph each) pointed at each other would get a good random flow.
<Is much better than standard powerheads.>
Thanks for the advice, and thanks for the recommendation on PA. Oh, one last question, would you recommend the pre skimmer box for the Remora?
<Yes. Not only does the skimmer box hide the pump, it skims water off the top of the tank which is often coated with organics. This can improve skimming efficiency by as much as 20%. James (Salty Dog)>

Quick water flow question 9/1/10
<Hello Lea!>
Yet another question for the wonderful WWM crew. Sorry for what may be a repeat question. I did try searching your site and couldn't come up with anything solid, other than a mention that you can't have improper flow - just improper dispensing of the flow, which is why I write. I am always grateful for all of your help, though!
<See what we can do.>
I have a JBJ 12 gallon deluxe nanocube. The included return output is a flare nozzle that seems to create quite the current in the small tank - my Percula seem to spend a lot of their time swimming against it and can't settle on my LTA.
<He chooses to swim against it, he can overcome the flow if he wishes!
LTAs are a poor choice in this size system. Size, stability and likely lighting are against you. See:
http://www.wetwebmedia.com/macrodoreensis.htm >
I would like to know if you recommend any type of retrofit device that will disperse the water more evenly. I don't want to decrease overall flow - I know circulation is important for the system, but would like my clownfish to be able to enjoy the LTA. Would a Hydor FLO rotating water deflector do the trick?
<I would skip this solution. Far cheaper and easier, look for a LocLine wye fitting and a length of pipe from the same. You will be able to split the flow, have it output from different points in the tank. One-way
laminar flow is not good, you will want two points of flow, ideally meeting at some point in your tank. Alternatively you could add a small powerhead.>
Also, the system seems to heat up a bit - any recommendations for good cooling fans for a small system?
<Anything that moves air! Keep in mind any tight fitting top will decrease the evaporative cooling from the fan. Plus, in such a small system you will need to top off the water constantly (maybe even a few times a day) to have the stability in this system needed. Even then, not really large enough for the LTA.>
Thanks for your help!
<Welcome, Scott V.>
Re: Quick water flow question (from 9/1/10)
Hi Scott,
Thanks for the advice in regards to the flow and cooling. I will definitely invest in the LocLine and give two points of flow. I've also seen the same tank with the rotating water device AND a Koralia powerhead
that attaches to the glass - if it seems I need more non-laminar flow have you had any experience with these?
<Oh yes, great powerheads.>
I guess I forgot to check my sources in regards to the LTA - I knew that a 12g was small for most/all anemones and had planned on just having the clownfish sans host, but one I bought (tank raised) was already associated with an LTA so I felt that it should continue that relationship. I used the WWM site to investigate both BTAs and H. crispa, but it seems all of my LFSs were out of anything but LTA. I'll keep an eye on him (he seems mostly happy - not moving and the gorgeous neon yellow coloring coming
back) and if he takes a nose dive I'll be sure to take him back and get something more appropriate - any suggestions there (even a non-anemone host - I've seen tons of FAQs on WWM mentioning "strange" hosts)?
<Just a bit of research on what will work and what you like!>
Thanks again!!

Circulation Advice (Detritus Accumulation) -- 01/17/10
Hi Crew,
<<Howdy Lynette>>
I sing your praises daily. You have been tremendous help with managing my saltwater and freshwater tanks and pond. Thank you.
<<Ah! We are pleased to be of service>>
I have a year old 120 gal reef with 30 gal Chaeto algae sump. It was created with contents from tanks that were 2 years old when I set up the 120. I have a large wall of live rock in the center of the tank running lengthwise. Various corals (mostly soft) growing along it. I have not been able to get my nitrates below 5-10 ppm (mg/L).
<<Mmm, actually this level is not/should not be too problematic (though I like to see a range of 5ppm or less). A 'small amount' of Nitrate is 'beneficial' to your coral's health/color>>
I have tweaked and adjusted, and finally think that my circulation is the problem.
I can blow off the rocks with a Maxi-Jet and days later the rocks are covered with gray sediment (detritus?).
<<Yes'¦along with some fine substrate material, maybe>>
I use a turkey baster almost daily to puff off the rocks as well. I have rearranged the 3 Maxi-Jet 1200 powerheads in every position w/ no avail.
<<Hmm'¦these may be insufficient to provide enough turbulent flow for this size tank>>
The return from the sump is a Mag-12 which is also directed to blow off rocks. I cannot seem to keep the front of the "wall" and the back clean at the same time and prevent a sandstorm or causing corals to retract from too much force.
<<Indeed'¦ The 'narrow' laminar flow from the pump/powerheads can often be difficult to utilize effectively. Rather than pointing the flow down at the rock, it may work better if you arrange the powerheads near the top of the tank and position them to converge their output streams along the upper layer of the tank, providing more chaotic flow to help keep detritus in suspension>>
I have Hydor rotators that I have used but nothing seems to help. I cut way back on feeding and even with that I still have sediment. It has also caused red slime algae buildup on the rocks. I am not opposed to rearranging the rockwork if needed
<<An 'open' structure to allow flow 'behind' the wall could help>>
and I am willing to bite the bullet and purchase other powerheads if they would do a better job (like the Tunze). I looked into the Tunze but wasn't sure what model and if it would even help.
<<The Tunze Stream pumps would be a good upgrade'¦lots of flow without the damaging effects to your corals from a narrow laminar water stream (though they can still cause damage if positioned to closely to livestock). I utilize the Stream pumps in my own reef system and truly love them. But if money is an issue, and considering you already have some Maxi-Jet powerheads on hand, consider upgrading each of these with a Sure Flow 1600 Maxi-Jet upgrade kit like this: (http://www.marinedepot.com/Algae_Free_Sure_Flow_1600_Maxi_Jet_Upgrade_Kit_Accessories_for_
For about $12.00 you can triple the flow from your Maxi-Jet powerheads as well as change the output stream to a wider, more coral-friendly flow type. The added water movement will certainly help with keeping detritus in suspension to be utilized by your corals or removed by your filtration system. I have experimented some with these units on my 375g display tank, and I am quite impressed with their performance>>
My salt is pretty stable at 1.025.
I do about 10 gallon water change weekly with well water and once every 4-6 weeks a 30 gallon change.
<<Mmm, your well water may be a problem re the Cyanobacteria. Very often, well water is not as 'pure' as we like to think, due to ground contamination from heavy metals/mineral deposits and/or agricultural runoff. I suggest you at least test this'¦and consider the use of a RO/DI unit for your reef's top-off and make-up water>>
I have a 760 watt PC/MH combo light that runs 12 hours for the PC and 6 hours for the MH.
<<The MH lighting period should be of a more 'Tropical' length of 10-12 hours'¦in my opinion>>
My calcium is about 300 ish - I can't get that up. I use the 2 part B-ionic system. This was my other problem. Not sure how to deal with this.
<<These two-part products usually work pretty well, perhaps the dosage needs to be bumped up'¦or'¦maybe your test kit needs replacement>>
It is difficult to read the pH card colors but I read it is 8.4. I have a Tunze 9010 skimmer that I need to clean 2x week.
<<A nice piece of gear>>
Blue hippo tang
Yellow tang
1 clown that resides in a rose tip anemone
Banggai cardinal
Pajama cardinal
Red Hawkfish
Flame angel
6 line wrasse
2 yellow tail blue damsels
Neon goby
Bi color blenny
Lots of Nassarius snails (at least 100 or so)
Brittle star
A handful of hermit crabs
Tube anemone
Frogspawn that has not gotten any larger!
Yellow polyps
Orange sun coral that is growing leaps and bounds!
Sinularia that will not extend
Trumpet corals that look great
Candy cane corals that look great and are growing
Many colored zoos all doing well
Red brain
Various mushrooms
Star polyps
Thanks for your help and advice. Any guidance is greatly appreciated.
Lynette Olson
<<Do try beefing up the flow as discussed'¦and look to that well water as a possible (probable) source of 'undesirables''¦ Cheers'¦ Eric Russell>> 

R2: Circulation Advice (Detritus Accumulation) -- 02/19/10
Hi Eric,
<<Hiya Lynette>>
Took your great advice.
<<Ah'¦I hope it proved helpful>>
Here is what is happening.
Apparently I did not need to supplement with the 2 part Ca/Alkalinity system as often as I had.
<<Not uncommon>>
I have backed off totally and I now have normal levels: pH of 8.2, Calcium is 420 ish, Alkalinity is 4.
I have 2 Tunze Streams and my Mag-12 return - got great flow going on!
<<Excellent again>>
Got a water filter - my top offs and water changes are now with water that is now 0 phos and 0 silicates. My nitrates are 0-5!
<<Looking good>>
Talked to Tunze about skimmer - seems to be running normally.
So why am I still getting Tons of diatom brown growth on my sand daily?
<<It can take a while for the system to 'rebalance.' Patience is a virtue here>>
My star polyp encrusting coral is covered with it. I clean stuff daily and it is back. Could my lighting be my issue?
<<Doubtful, in my opinion'¦but do peruse our FAQs on Diatoms for others input: http://www.wetwebmedia.com/diatomfaqs.htm >>
I have 2- 240 watt HQI MH and 4-21" 50/50 CF . The bulbs were new in June/May '09. Could the Kelvin not be adequate?
<<Anything suitable/acceptable for marine/reef aquaria will be fine>>
I run all 4 CF 12 hours daily and the MH 6 hours daily ( have been bumping the time up slowly per your recommendations).
<<Ah, very good>>
Once again, thanks so much for your expert advice - it means a lot to us beginners.
<<Is my pleasure to assist'¦ Give the adjustments/improvements you've made some time to effect a change. Continued maintenance and observation for now my friend. Be chatting! Eric Russell>>

Water Flow for a 150 Gallon Reef Tank -- 01/21/10
Greetings from Canada,
<<Back at ya from South Carolina!>>
I have a Mag -Drive12 in the sump , returning water through two outlets into the tank , which is 24 inches x 48 inches x 28 inches high , and obviously, I think, not enough flow.
<<Mmm, depends on the organisms kept and also how these 'outlets' are positioned>>
I am thinking of putting a Koralia 4 in to help,
but is this enough?
<<Dunno'¦ If this is a SPS/Acroporid dominated tank then a 'pair' of these would likely be of benefit (arranged to merge/collide output for some chaotic flow)'¦otherwise'¦yes, this is probably sufficient>>
Perhaps you could suggest a "combo' of these, i.e. 2-4's or perhaps 2-3's?
<<I can't give you an informed answer without better information re your livestock and stocking densities'¦but most any reef-keeper's system can benefit from more flow'¦either of the combinations you list should be fine>>
Also, correct me if I am wrong, but don't these just plug in to an outlet, as I don't want a wavemaker or any controller?
<<Yes'¦ There are two types of these units available now, just be sure to get the 'standard' units not meant to be used with their proprietary controller>>
One last thing, please.
When this Mag12 goes, should I replace with same, or perhaps bigger?
<<Can your overflow/s handle 'bigger?' Even so, I doubt there's a need'¦though you might consider going 'better' with something like the offerings from Eheim>>
Thanks for all of your help, and to say I am a regular on your site.
<<Happy to assist'¦have you read here and among the linked files (http://www.wetwebmedia.com/circmarart.htm)?>>
Kind regards,
Ted Stasso
<<Cheers'¦ Eric Russell>> 

Re: Circulation Advice (Detritus Accumulation), & Aiptasia chem. f' -- 01/22/10
Hi Eric,
<<Hey Lynette>>
Thanks so much for your help and advice.
<<A pleasure'¦>>
I ordered a Tunze stream and silicate and phos test kits.
I am unfortunately at my wits end. I cannot keep up with this slime; it is starting to cover my corals.
<<Hang in there mate'¦it can be beat. I assure you, you are not alone in this fight. Most every hobbyist will/does battle this'¦and very often more than once>>
I don't understand why this has resurfaced on a cycled and relatively stable tank.
<<Conditions became optimal for its progression'¦ Unfortunately, once established Cyanobacteria are a tough opponent to eradicate. Aside from correcting any chemical/bio-mineral imbalances, the persistent 'manual' removal (siphoning) of this blue-green alga is important to beating it. It is though that the 'persistent' manual removal somehow triggers a chemical reaction that helps with its eventual demise'¦but at the least, regular removal helps with letting the more desirable 'chemical users' within the system to progress and out-compete the Cyanobacteria>>
Please note that I have never had problems with my calcium (low) or pH (high) or this heavy of slime.
<<And again'¦what you are experiencing is in no way unique>>
I checked my nitrates again the other day and they are no longer stable at 5-10 they are getting higher!
<<You REALLY need to determine the source of this. I urge you to pre-filter you well water>>
I have never tested my well water since I have not had any problems for 3 years
<<These problems are likely a result of 'accumulation''¦and very possibly of elements you wouldn't/can't test for. Again I stress'¦pre-filter that well water before using it in your reef system>>
....I have had some events occur over the past 2-3 months and I am wondering if you thought they could be a cause.
<<Let's take a look'¦>>
1. Several months ago I added about 200 Nassarius snails
<<Mmm, too many I think (120g tank)'¦starving/dying snails are not going to help for sure. Even if these are the little guys (max size about ¼'), you should start with about one for every three gallons of tank capacity, in 'my' opinion. If conditions are right for their continued prosperity, they will quickly breed and adjust their population density to whatever the tank can sustain>>
to help keep the sand bed churned. I wonder if the new disruption of the bed has caused silicate to "leach out".
<<If these and other ions (e.g. - Phosphate) have been accumulating and become sequestered in the sand bed, yes, the actions of the snails may expose such to the water column. But these detritivores are still very beneficial to your system>>
2. Another problem is I have been fighting Aiptasia.
<<Another 'common' malady'¦and a battle a bit more easily won (though don't ever expect to truly win the 'war')>>
I have tried various methods with no luck. A LFS suggested formalin 1-2 cc injection into the Aiptasia with a hypodermic needle.
<<Mmm, too risky to the biological filter/system as a whole for my liking. Please do read here: http://www.wetwebmedia.com/formalinart.htm >>
Of course I was very skeptical and did some research finding nothing.
I talked with several staffers at the store that service local tanks for Dr. offices and they all report they use this. One of them even squirted about 5 or 10 cc directly into a display tank filled with corals and clams etc.
Desperate, I tried it on some of my largest Aiptasia.
<<Mmm'¦ Please don't do this. There's no true panacea for this pest anemone, but have a look at/give a try to Aiptasia-x from Red Sea. This is the best performing product for eliminating Aiptasia I've seen/used in decades'¦and much safer to your system'¦and to you!>>
Ironically shortly after this (which is about 4-6 weeks ago) I lost several corals that had been flourishing - xenia, bubble, yuma, taro tree.
<<Very possibly as an indirect result of injecting the Formalin in to your system (via the Aiptasia)>>
3. Another incident was the skimmer issue. I had been running a Remora Pro but I was not getting adequate skimmate so I decided to upgrade to the Tunze 9010. It was running great until shortly after Christmas, the pump went. I took about 12 days to get the new pump which meant no skimmer running.
<<This is not likely a large factor here>>
I did several water changes during this time frame. Now with the new pump it is not producing very much skim at all despite air valve adjustment.
<<This is possibly a result of your increased water changes, maintenance/cleanup, and reduced feedings'¦give it some time>>
4. I had a sea cucumber (baby poop yellow/brown color) that only lasted about a week or so.
I managed to find the dissolving mushy carcass and remove most of it but I wondered if this could have polluted the tank.
<<Very likely, yes>>
Could any of these be a culprit?
<<Any or all may be contributors'¦but I still can't help but go back to your use of unfiltered well water>>
Please note the fish have been great through all of this.
<<Just 'less affected''¦for now>>
I can't thank you enough for any help you can throw my way.
<<I'm happy to share'¦ Eric Russell>>

Re: Circulation Advice (Detritus Accumulation) -- 01/30/10
Hi Eric! It's me again...
<<Hey Lynette!>>
I have updates just in case you wanted to know.
I tested everything: TAP water is 0 for phosphorus but off the charts for silicates (> 25), tank water is .2 for phosphorus and 0 for silicates (weird huh?)
<<Nah'¦ Though a prime suspect, tap water is not the only avenue re the phosphate (e.g. - foods, salt mix, supplements, etc. '¦even contaminants from your skin)>>
Re-checked tank water for calcium (with a new test) I am estimating about 350 ppm, tank water pH is >8.6.
Tank water is off the charts for alkalinity as well, I think it is about 5
<<Do stop all supplementations for now'¦and also test your salt mix>>
My actions;
1. Put in the Tunze Stream 6085 and ordered a Nano Stream as well. These in addition to the Mag-12 sump return should be adequate circulation right?
I pulled out the MaxiJets.
<<It wouldn't hurt to leave these in/use to get flow behind your rockwork>>
2. Put in a media bag with PhosGuard to bring the phosphorus down. I just took it out yesterday and I am going to retest phos.
<<While the passive use of this media in this manner will help 'some''¦a much better approach would be to actively utilize it in a 'reactor' such as this (http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=20173). And as much as I like Seachem's product line, I'm a bit leery of their aluminum/alumina based Phosphate remover. I feel a safer and even 'more effective' alternative is the iron-based Phosphate removers available like this (http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+8057+13963&pcatid=13963). I utilize this reactor and media combo on my own reef system as routine>>
3. I am adding the calcium portion of the B-ionic 2 part to bump up the calcium but unsure of how much or how quickly to do this.
<<Rather than the possible seesaw back and forth re, I think you are better off reestablishing your tank's equilibrium with a couple moderately large water changes (30%) a couple days apart as needed'¦and hold off on any supplements until testing shows a requirement, and then use the two-part additive as suggested by the manufacturer>>
4. Do not know how to get the alkalinity down
<<Suspending supplementation and performing partial water changes should restore equilibrium'¦assuming your salt mix is not at fault here>>
or even why it is high?
<<Something you're adding to the tank'¦or something already in the tank. Also, did you test your tap water re? ...and its pH?>>
5. Gave at least 50 of the Nassarius snails to the FOWLR tank I take care of at a Dr. office.
6. Used some Aiptasia-X and got some of the big ones. Often times it does not kill them, only "stuns" them and they are back in a few days.
<<Indeed'¦a very 'durable' organism. Persistence is key'¦and I do think the Aiptasia-x to be the best product for the job here>>
I failed to mention that I am trying to breed some Berghia Nudibranchs in a 10 gallon to rectify the anemone problem once they are large enough.
<<Good luck with that'¦please do let me know how this progresses>>
7. Still not getting good skimmate. I have the skimmer in a section of the sump where 2 - 1 1/2" hoses drain in from display tank. The wall dividing this area from the center area with macroalgae allows good flow but keeps enough of the raw tank water contained. Could the strong flow coming in from the hoses be adversely affecting the skimmer?
<<Doubtful (my setup is very similar to this)'¦ I just may be your tank has little to skim at the moment>>
I have 3- 1 inch U tubes draining into these hoses so it is a good bit of water. What about the air adjustment screw? It is in a middle position but I have tried all positions w/ no change in skimmate production.
<<This is a Tunze skimmer if I recall'¦try contacting Roger Vitko at Tunze USA re its adjustment>>
Once again I must say how much I appreciate the advice.
<<Is my pleasure to assist>>
I am a Registered Dietitian and I was required to take multiple chemistry courses in college for my degree but this stuff has me baffled. I even work with IV feedings in an ICU where I must deal with electrolytes like phosphorus and precipitation with calcium. How could this be happening with my tank? Good thing I guess it is not a patient....
<<Hee-hee! Ah, but it is!>>
<<Press on my friend'¦you'll get there, in time. Oh yeah'¦back to your use of unfiltered tap/well water. There are just too many 'unknowns' that you could be introducing to your reef'¦I still strongly feel you could only benefit (and maybe even resolve much of your issues here) from investing in a RO/DI filtration unit. Cheers'¦ EricR>>

Re: How to kick start the new setup? 6/13/09
Thanks for all the insight.
Here is where I am confused now about the GPH. I am not thinking of getting bigger holes drilled. I have read that to keep FOWLR and some mixed corals the flow should be 10X - 15X and for SPS should be 20X - 30X.
<Fair estimates.>
That said, I only have 600GPH on my 150 gallon tank. I will also use a pair Koralia PowerHeads (model 6) each one is rated 2200 GPH. If I do this, can I say that my total GPH is 2200+2200+600 or somewhere
close? Or am I completely wrong in calculating the 10X and 20X flow rate?
<Nope, you are on the right track here.>
I know a lot of people use AGA drilled tanks with 1 inch inlets and have kept SPS corals with success.
<Oh yes, just be vigilant. With these bulkheads at full capacity the smallest of obstructions (snails, algae, etc.) can lead to overflow blockages and water on the floor. It can be done no problem, but that is the issue.>
Thanks again for the help and time.
<Welcome, Scott V.>

Re: System Setup, Plumbing, Pumps 5/26/09
Thanks for your response.
I'm conflicted, though: we want 10-20 times turnover per hour, right?
750 gph is more like 5 times per hour. Would you then recommend other circulation, e.g. powerhead(s) within the tank and/or the construction of a whole new closed loop?
<Yep. Your overflow will only support so much, it is not really desirable in many cases to run all flow through the sump anyhow.>
<Welcome, Scott V.>

Re: Plumbing and RDP [Scott V]  4/20/2009
Thanks Scott!
<Welcome Jeremiah!>
Heh, either way I go, with the eheim 1262 sump return at about 700ish I'm looking somewhere around 3100gph, 41 times tank volume per hr! Sick!
Think that's enough...haha. Thanks again man!
<Me too!>  

Biotopes and Water Circulation in Closed Systems   2/25/09 Dear Crew: <Benjamin> Confused here, as usual. No tank yet, just trying to do my homework and plan as best I can. High water circulation seems to be touted as the ultimate goal for a closed system reef aquarist yet there seems to be a sizable number of species that thrive on slower flow rates. <Yes and yes> Please point me to the articles, or perhaps explain in terms of actual functionality how these seemingly contradictory facts play themselves out in an actual tank setup. <Don't know where you might find this information specifically... on the Net... Better for you to spend some time in a library: http://wetwebmedia.com/litsrchart.htm> Lets say, for example, a biotope common to slow moving currents and a biotope with fast current needs. I plan on a tank that turns over its volume 15 to 20 times per hour. What biotopes would that suggest? <? That you investigate your possibilities... A particular area geographically? Depth, topography, habitat, "key" species... Many places to start. Bob Fenner> Thank You, Benjamin

System water flow... overall circ. and refugiums      2/22/09 Dear Crew: <Ben> It is my intention to create a high flow system with sump and refugium. Having read quite a few postings on DSB's, sumps and refugiums I have gleaned what seems to be contradictory advice. This may be due to my ignorance (as opposed to stupidity) of a specific contextual frame I do not understand, ergo I write. I have several questions please. <Ok> 1) Are high flow rates recommended to maximize biological processes, to make the creatures feel more at home or both? <Can be a combination of these ends... though it should be mentioned that there is a need to define terms like "high", and that there are circumstances, processes, organisms that prefer "lower" rates of flow> If it is primarily the former then it would be of little use to utilize a additional pump and plumbing circuit for the sole purpose of water movement in the tank? <Mmm, w/in relative terms, settings, there are exceedingly few systems that are over-circulated> 2) I intend to use a 6" DSB in the tank, sump and refugium. The goal is de nitrification and the propagation and maintenance of a healthy population of sand dwelling critters. Some articles/comments have suggested refugiums should have a slow rate of water flow while others suggest a fast rate. <Depends on a few factors... for the refugium sake itself... 5-10 times turnover is about ideal... but there are often other uses that call for more turns> Both slow and fast flow rates were suggested as optimal for de nitrification!? <Actually... flow rate in the water surrounding substrates where denitrification occurs are of little influence> Is the fast rate just for the main tank and sump? <Mainly, in most cases, yes> Should the flow rate to the refugium be slowed or not? <Should be, yes> Do you have a suggested rate or range of flow rates for the refugium? <Yes... 5-10 times vol./hr.> Gross tank volumes planned are 150 for the main tank, 50 for the sump and 50 for the refugium. I have yet to calculate probable net water volume but a good guess would be about 145 to 175 of actual water. I plan to turn that over somewhere between 15 to 20 times per hour. <Okay> 3) I have read some advertisements/articles re: the New Marine Series Marineland tanks and feel their proportions of dimensions offer several advantages. <They do indeed. These are (surprisingly to many) well-thought out units> They rate their overflow boxes (2) at 700gph each which in ideal circumstances would give me only 1500gph return capacity or about 8.5 turns of the tank per hour. Perhaps I should be thinking of a DIY tank or have someone make one already drilled for my flow rate goals? <This is the rule rather than exception unfortunately. I would "supplement" the drilled options here... by either drilling more holes or adding an over the back "closed loop circulation" system> Except for perhaps the feed to the refugium I would like to use 2" plumbing throughout the system in conjunction with a very high GPH pump. <Okay> Thank You Benjamin <Welcome; thank you for sharing.... Do feel free to chat further... am going to place your query in ScottV's in-folder for his resp. individually. Bob Fenner> <<Hi Ben, I do believe these use the standard joke of a throughput size, 1" for the overflow drains like most pre manufactured "reef ready" tanks...you will in reality  only see 300 gph per. As Bob stated, you will want to add more one way or another...it does not sound like you actually have the tank in hand yet, now is the time to get one with larger throughputs! Either custom from the manufacturer or do consider drilling it yourself. Most any manufacturer will drill your holes larger from the factory for an up charge. If you are at all mechanically inclined or have somebody you trust who is, drilling the glass yourself is very easy/straightforward, really kind of fun and darn cheap! A few links for you drilling: http://reefercentral.com/Videos.html why 1" overflow throughputs stink: http://wetwebmedia.com/SystemPIX/PlumbingPix/Oneinchart.htm I hope this helps out, feel free to write back with any questions. ScottV>>

Re: Power Filters ATTN Minh, plus now fluorescent tubes, circ. for cnidarians    1/14/09 Minh, <Hello John.> So now you are fairly familiar with my system and you had asked about my fluorescent tubes. Well lets just suffice it to say that once before I had a reef tank and decided to upgrade the lighting already. I purchased a 260 watt PC fixture. It comes with the usual arrangement of 2 10K Kelvin lamps and 2 Actinic lamps. Thinking of replacing the actinics with 10K Kelvin lamps. <Congratulations on the purchase.> I know this is not enough light for SPS or clams or many anemones but I would like to keep some soft coral like the toadstool. Perhaps an LPS like a frogspawn. <Although some Acroporids may actually need higher intensity illumination, Power Compacts may be sufficient for Montiporas and LPS if creative aquascaping and coral placement is utilized.> I realize that keeping a shrimp with a frogspawn is dangerous so I would not do it. <Shrimps in the Lysmata family such as Scarlet Skunk Cleaner Shrimp (L. amboinensis), Peppermint Shrimp (L. wurdemanni) and Blood Red Fire Shrimp (L. debelius) are opportunistic scavengers and may damage coral flesh when going after uneaten food in the coral's oral disc. Likewise, hermit crabs in the Calcinus <sic> family or crabs in the Mithrax <sic> family can also do similar damage. Coral Banded Shrimp (Stenopus hispidus) and "Yellow" or "Dwarf" version (Stenopus scutellatus) have less of a tendency to do so. Although all of these species have been housed in many tanks with Euphyllia without issues, keep in mind of the possibility of damage.> Also to let you know I purchased an Eheim 2026 and that should be here next week. So much for FOWLR. Once you cross over into a reef tanks there is no going back I guess! <It is an excellent filter, I suspect you will be happy with it.> My only concern now is will 2 Koralia 1's provide enough circulation for corals that may require I higher flow. I am sure they are fine for most leathers, the mushroom, polyps, etc. I just have no experience with Koralias. < The Hydor Koralia is from the new generation of low-cost propeller driven pumps that is quite different to the powerheads and pumps you've used in the past. Instead of generating a forceful jet of water flow, its large prop and shroud design allows for a gentle wave pattern that is much more efficient at moving water than a traditional impeller driven pump. The two Koralia 1's and the flow from the Eheim 2026 should be sufficient for most of the corals you intend to keep. Gorgonians are the exception as these requite more flow but with creative aquascaping and placing the specimen closer to the powerheads, you can work around the issue. For an excellent read on efficient flow design in a reef tank, take a look at this article: "Water Flow is More Important for Corals Than Light" (http://www.advancedaquarist.com/2006/6/aafeature2).> Thanks again Minh. I have really enjoyed communicating with you. John <You're welcome. Cheers, Minh Huynh.>

Water Movement for Debris -01/11/09 Hello Crew, Hope all is going well. I have read that a strong enough filter in an aquarium will provide proper water movement to keep the debris stirred up in the water column to be drawn in to the filter. But just as a backup, if I used 2 powerheads to do this how would I position them to get the max effect on the substrate? And in a 75 gallon tank would one powerhead be enough with a sand bottom. Thanks for all your help. James <For this I would suggest something that's come to be called "blasting." Every once in awhile you take a powerhead (in your hand) and "blast" the rocks (and to a lesser extent the surface of your sand bed). This will stir up debris much more effectively. I have done this many times myself and think it is a really good way to get debris into circulation. It will cloud up your water for about a day or so, but it is a good method for "cleaning" up the rock and everything. Best, Sara M.>

Re: Water Movement for Debris 01/13/09 Hello Sara and thanks for the info. I have another question please on a similar topic. I have read and been told that it is crucial that a filter on an aquarium circulate the volume of water in the tank by at least 4 times per hour but preferably more. If I added a powerhead or 2 does the gallons per hour those put out count, or is the recommended ratings just apply to the filters itself? Thanks again. James <This is going to be mostly a matter of opinion. In the case of reef aquariums, IMO, yes, the powerheads do "count" because they push water around the live rock, which is a form of filtration. However, they might not "count" as much because they're not pushing the water through a protein skimmer or any "actual" filter. I'm sorry if this isn't very helpful of an answer, but it's really a judgment call on your part. If your nutrients are high, or if you otherwise think you need more filtration, then the powerheads might help, but likely not as much as adding a protein skimmer or other form of filtration. Best, Sara M.>

Turnover rate explained... note to fix link 12/26/08 Dear WetWebMedia: <Hello.> I successfully ran a 55 gal saltwater tank using an ancient undergravel filter (many) years ago. I'm planning on setting up a new 180 gal tank (fish and hardy inverts) using the more modern external sump / wet-dry system including some live rock. <You will like this setup much more.> I just wanted to ask a basic question regarding turnover rate. I've searched the site and found many listings regarding proper turnover rate etc. If I'm planning on a "turnover rate" of 10X per hour, this would be 1800 gph. My question is this: This value of 1800 gph, is this literally 1800 gallons of water pouring into and out of the sump per hour? <Not necessarily. You will want a minimum 10X turnover inside the display (more depending on what you wish to keep), not all need route through the sump. Depending on your sump size 1800 GPH may be tough to handle in regards to microbubbles in your return line and noise. You can run something reasonable through the sump like say 10X the sump volume per hour and then amend the flow inside the tank with powerheads or a closed loop.> I just want to make sure I understand turnover correctly so I could size my equipment accurately. If this is correct, I planned on using two 1.5" PVC overflow tubes to feed the sump, would this be optimum? <In all likelihood you will end up with 700-800 gph or so through the sump, in which case two 1.5� drains will be fine. For 1800 gph you will need dual 2�, adding a third to achieve some redundancy in the overflow should a drain fail.> Thank you in advance! Marcus P.S. On an unrelated note I tried to open the "heater impressions" article on heater recommendations but the link wouldn't open. <For me neither.> Would you have any recommendations for a really good brand of heaters? <My first choice are the Jager heaters, tried and true.> I want to use multiple heaters and divide the wattage since this is safer than having one big heater, I just wasn't sure of which brands / models were good. <This is a good idea!> Thanks <Welcome. Happy Boxing Day, Scott V.>

Water Movement 9/23/08 Hi Crew, <Hello Sam.> I have a 6 year old 10 gallon setup with live rock and sand, a penguin mini filter, 65w PC's, Candycane corals and some fish (more than you would approve). <'¦You said it!> I began having Cyano problems a few months ago. It started, I think, by my not changing the bulbs in time. <Or finally seeing the consequence of overstocking, as you say it.> It has improved but it is still there. When I do a cleanup it now takes a week till it is bad instead of overnight. I cut down feeding to once a day and I keep the lights off 2 days a week every once and a while. I have a small power head (rated 130gph) that faces the length of the tank. Would it be a good or bad idea to place it in mid tank facing the width. <It may help, but there are likely other fueling factors here http://www.wetwebmedia.com/bluegralgae.htm.> It would probably hit the glass and divide itself in both direction which would probably be a lot more movement all around than what I have now. I know you guys think it is never too much movement so I am not sure why I am asking. <There can be too much, specifically of the laminar type: http://www.wetwebmedia.com/circmarart.htm. Again, not likely the culprit, other factors here. > But I haven't emailed you for a while. Thanks Sam <Welcome, Scott V.>

Plumbing and Pump 9/22/08 Hi guys. <Vince> I have read so much that my head is swimming with ideas. I want to re-plumb my system from scratch to make it appropriate for hard/soft corals and everything in between. My DT is a 220 gallon (72" x 24" x 30") All-Glass aquarium which is to say that the two glassed in boxes with the holes underneath accommodate 1.5" ID and 1" ID piping. In other words, my absolute maximum drain capability will be two 1.5" and two 1" drains. I have read that 1.5" does 600 gph and the 1" does 300 gph, but I can't figure out if these numbers are for one or two drains. (Does a single 1.5" drain do 600 gph or 1200 gph?) <A single 1.5' is good for about 750 safely, while 300 is correct for the 1'.> The 1" ones are currently plumbed for return lines, but I am willing to use them as drains and just have my returns hanging over the back, which actually increases my return line and wavemaking options (Can we say "8 way Ocean Motion"?). My sump is a standard glass aquarium that already has a hole drilled with a 1" ID bulkhead from which the main pump can draw water. I do NOT want to drill a new hole to accommodate a larger pipe. I intend to keep approximately 30 gallons (half full) in the sump. So, for my intended bio-load, I understand I ought to have 10 to 20 times my DT gallonage turnover, which is to say 2,200 to 4,400 GPH flowing from DT to sump back to DT. <You will want 10-20 times turnover for total flow, it does not all need to transit the sump. > <Perfect.> I also will have two Koralia 4 water fans just to create circulation in the DT. (The 2nd one has yet to arrive, so I have not had an opportunity to experiment.) I have read one suggestion that if I put one at mid-height in a back corner and the other one mid-height at the center of the back wall and aim them both at the dead center of the tank, that the turbulence created by these positions will simulate gentle wave action. <You'll just need to experiment with different placement of the powerheads in relation to your sump return.> So, here are my questions: 1. What GPH do I need going into and out of the DT? <I would shoot for around 1000 gph or so on this tank. This will be a manageable level through the sump and puts you around 3000 gph of flow in the display with the powerheads.> 2. Are the two 1.5" drains sufficient to accommodate that GPH? <Yes, although using the 1' drains also just provides that much more redundancy.> 3. Will the positioning of the two Koralia's actually create a turbulence to simulate wave action? <With a little experimentation in placement it definitely can. I would actually start with the two on opposite ends of the tank, pointing at each other. Mix in your sump return flow and then start tweaking it here and there until you are happy with the flow. A bit of positioning info in this article http://www.wetwebmedia.com/circmarart.htm> T.I.A. Vince. <Welcome, have fun setting up, Scott V.>

Enough Flow From Return Pump? -- 09/10/08 Dear Crew, <<Greetings Art>> I have a 65 gallon tank with a built in overflow rated at 600gph. <<Mmm'¦I'm going to guess this is a single 1' drain'¦which means your overflow rate is more like 300gph, in reality>> Under the tank I have a wet-dry filter with a submersible Via Aqua 2300 water pump returning water to the main tank. <<Hmm, with headloss this pump (rated 600gph @ 0') may work out here'¦though I would recommend installing a gate-valve on the output side of the pump to temper flow if needed>> Recently, I considered installing a closed loop" system but haven't moved forward with plans because of the inadequate flow from my return pump. <<Indeed'¦although returning water from an 'open' sump in no way entails a 'closed-loop.' I believe what you are considering is a simple 'return manifold''¦and with flow requirements of 350gph+ for a single ½' nozzle (to achieve some purposeful flow), you hardly have the pump or drain to accommodate. Best to use some other means of increasing flow (powerheads, etc.)'¦or install a 'true' closed-loop (see here and among the associated links: http://www.wetwebmedia.com/pbretfaq2.htm )>> According to the manufacturer the return pump should be pumping 300gph with a 4' head. When I tested the pump, my results indicated a flow rate of only 120gph. <<Not surprising'¦the pump you have is not 'pressure rated.' Most all the submersible magnetic pumps available will require you to get something a bit larger than you think you need if you wish to maximize the drain capacity of your system. And again'¦I urge you to install a gate-valve on the output side of the pump to allow you to adjust this flow as need to quiet things/prevent overflowing the tank I removed the wet-dry tray containing floss filter material, and timed how long it took to fill a 1 cup measuring cup from the return line. It took approximately 2 seconds to fill the cup. When I did the math I came up with, 16 cups (1 gallon) x 2 seconds = 32 seconds per gallon. I rounded that off to 2 gallons per minute x 60 minutes = 120gph. <<This is useful data, but utilizing a larger measuring device (i.e. - gallon container) would likely yield a more accurate result. Although, a few more gph either way is probably moot>> I'm no expert obviously, but it seems that this pump should be pumping much more water than it is. <<Some of the better pumps will'¦I do not consider this pump one of these. But I can only make assumptions without much more information re your plumbing configuration. For instance, every fitting between the pump and the terminal end of the output will add about a foot of head-height/head-loss to the pump. Reducing line diameter to anything less than the diameter of the pump output will also reduce flow. Any/all of these coupled with the height and/or horizontal length of the plumbing line can greatly reduce flow rates. If you wish to increase flow'¦you are going to need a bigger pump>> My entire system, including pump, is only about six months old. <<Some small buildup of bio-film in the plumbing lines is also contributing to a reduced flow rate. I always recommend folks purchase/utilize pumps a bit larger than needed'¦with a gate-valve installed to adjust flow as necessary when/as the system ages>> Anyway, I have two Hydor Koralia power heads in my main tank each rated at 800gph. <<Excellent>> So, I have just over 1700gph of total flow. I am considering a new pump, and would appreciate your opinion what I should do. <<I think I have stated such>> I know I would need much more water flow from my return pump should I decide to install a "closed loop" system. <<See my previous comments re'¦ This would not be a true closed-loop'¦and you don't have the drain capacity to power a return manifold nor do I think you would be happy with the noise/bubble issues if you did. If you wish to increase flow without powerheads then do research the closed-loop further'¦and shoot questions back to me re if you wish>> Thanks in advance for your help. Art <<Is my pleasure to assist. Eric Russell>>

Too much circulation? 8-13-08 Heya WWM Crew, <Morning, Mike here> I was glad to hit the Donate button and send some "green" your way...just sooo much good stuff on this site. <Much appreciated, on both counts. We try!> I am setting up a 75 gal Marineland Cornerflo tank. The overflow is rated at approx. 700gph through the 1" bulk head. I am returning water via a Rio Hyper Flow pump rated for approx. 660gph. at 4ft. I had to plumb a ball valve in the return line to tone down the return. The overflow couldn't keep up without slurping frequently. In the tank, I have two Koralia 3 powerheads rated at 850gph. They are in opposite corners (one 8"-10" high, one 12"-14" high) pointing diagonally towards front glass. <lots of good water movement there...how about splitting that return into two, or have you done that?> 1st Question: Should I adjust the ball valve on the return so as to pump approx. 2 to 3 times tank volume (approx. 200gph to 300gph returned)? I have a 30 gal sump with an in-sump skimmer. Or, should return of water be much greater...in the area of 550 to 600gph? <I'd crank it up, and split the returns, or move through a wider opening for less laminar flow> 2nd Question: Are the Koralia's too powerful for my tank? The reason I am concerned is that the turbulence is causing slight sand drifts as the currents bounces of each other and the front glass...and I don't want to "current" my future fish to death. Koralia also has smaller powerheads rated for 400gph or 600gph...either of these better suited for my tank? I definitely have great circulation now...just not sure if its counterproductive. <Go to a reef sometime, and THAT'S where you'll see a "lot of flow"! Telling me what the tank is designed to house would be nice, but I would say don't worry about it, this is a good thing and it occurs in all of my aquariums. Remember, it's almost impossible to have too much random, turbulent water flow for reef species!> Thanks a bunch, <Anytime, thanks for your support> Phil in Mississippi <M. Maddox in Texas>

Nano reef & natural water movement, 8/4/08 Hello guys and gals! <Hello> I have a small 10G nano reef tank, close to 1000 G/Hr water movement/circulation. The temperature is between 78-80 F without using any chiller. It has been set up bout a year now. I have a very healthy and good lookin' livestock. So here I come with the question of the century:-) I was always wondering how many Gallons of water exchanges in an hour in the natural seawater? Is there any estimate on this? I'd love to know that! <From diving I can tell you lots, even in relatively calm areas you are still talking about a complete change of water every few minutes at most, every minute or less in areas of stronger current. This is why many people say you cannot have too much flow.> The other thing I was wondering about if you accept any kind of donation, or anything like that. I'd love to appreciate all the efforts you guys put in this website. It is like a library for me. <I believe we have a "begging box" on the front page.> Thank you for your time and answers, have a salty day! Sonny <Thanks for the note.> <Chris>

Hydor Koralia Question 4/24/08 Hi Bob, <Scott V. here with you.> I have looked through your site many times and it has been quite helpful. <Great!> I have a FOWLR 72 gallon bowfront tank with an Eheim 2026 filter and was looking to replace my powerheads with Koralias. I currently have a couple of smaller clown fish in the tank and would like to get as much water flow as possible. Would 2 Koralia 4's at 1200 gph each be too much for the clowns? <The clowns can handle the flow, this will put your tank turnover past 30 times and hour, fairly high for a FOWLR. Not that this is necessarily a bad thing, but dual Koralia 3's will be a better fit for this in my opinion.> The only other additions to livestock I may make would be smaller reef safe wrasses. I know these types of questions are beaten to death on your site, but would really appreciate a response. <No problem, we respond to all.> Thanks so much, Dustin <Welcome, enjoy the tank, Scott V.>

Low Flow? Algae!! 4/16/08 Hi Crew, <Hey there Mark.> I have a 90 gallon soon to be reef tank (I hope). It has been set up for about 6 months with a Tom's overflow box and a sump/reverse cycle lighted (140watts daylight) 29 gallon refugium using a Hagen 70 powerhead as a pump. Using the macroalgae Chaetomorpha in refugium only. Protein skimmer is a Tunze DOC 9005 and is in sump. Lighting is a 175watt 10K metal halide. Water movement within the display tank is provided by a Hydor 4 powerheads. <It all sounds nice!> Only additive is Kalkwasser to replace evaporation. Inhabitants include algae, copepods, and 3 turbo snails. Water parameters include: ammonia and nitrite=0 nitrate < 5ppm phosphate < 0.5ppm calcium = 360ppm alkalinity = 9-10dKH salinity = 1.025 pH = 8.4 morning and evening Problem: Derbesia and Cyanobacteria in the display tank but not the refugium. Is it due to lack of flow? <Hmm, no, you should have plenty of flow. Perhaps look at you implementation of the flow, make sure it is directed in a way to prevent any 'dead spots'.> I thought that maybe because my pH is so steady (and it wasn't before I set up the refugium) that the flow was OK. <A refugium can sure work wonders toward PH stabilization! Take a look at your make up water. Your nitrate and phosphate are high for a tank with no fish or substantial livestock at all, especially when you consider your use of a macroalgae refugium. Unless you are adding something to the tank (food, food additives) your water source is very likely the problem.> Thanks, Mark <Welcome, good luck, Scott V.>

Re: Low Flow? Algae!! 4/17/08 Thanks for the rapid response Scott. <You're welcome my friend.> I wasn't very clear about my PO3 and NO3 levels in my last email. I meant to say they were 0 but only detectable to 0.5ppm and 5ppm respectively. <Okay, understood.> That being said I am using tap water. The city's water quality report states 0.0ppm NO3 with a test kit that can detect down to 0.4ppm. However it does not test phosphate (though phosphorus is 0.01). Of course the best PO3 and NO3 test kit of all (algae) indicates I need to use RO water. <Considering the addition of no food to this tank, yes, an RO is a wise investment. Regardless of the tap water quality, I am a proponent of RO use for the sake of consistency if nothing else. Tap water will vary throughout the year.> I just wanted a second opinion as to whether the Hagen was producing enough flow between my sump/refugium and my display. <I have had very successful systems with flow this low through the sump, sometimes I get stingy on electricity and do not want to pay to pump water up and down! More, 600-900 gph after head pressure is accounted for, is desirable for a system this size.> Thanks again, Mark <Welcome, happy reefing, Scott V.>

Return Pump Flow--How Much Is Too Much? -- 02/18/08 Greetings WWM Crew, <<Hello Bill>> Here is my situation. I have an AGA 180-gallon RR tank with the 'MegaFlow' system--sort of. <<Mmm'¦>> The ¾-inch return is now 1-inch, and the drains are 1 ¼-inch instead of 1-inch. The 'MegaFlows' have been replaced with Durso's. <<I see'¦ I do hope this means you increased the size of the holes/bulkheads in the tank'¦not just an upsizing of the pipe>> I drilled out the 'teeth' in the overflows and siliconed black plastic gutter guard in its place. My tank has an Ocean-Motions 4 way Closed-loop plumbed according to Paul's suggestion. This all drains in to an 85-gallon 'fuge, <<Sweet>> and then to a 90-gallon sump. <<Really sweet>> My skimmer is in the sump. The return I was using was a Mag 1800, and up until last Tuesday it worked fine--then BAMM. <<Hate it when that happens'¦ I have used these and do think the Mag-Drive pumps usually serve pretty well, for the money'¦but I made the 'switch' to Ocean-Runner a while back and have been very pleased with the result'¦and when/if you can get them big enough, Eheim is even better>> A friend of mine that owns/runs an LFS said he had a 'new' (used for 5 minutes) pump he would sell me, so OK, I'm good to go right. The pump is an Eco-Plus rated at 4950gph. <<Yikes! Much too much flow for your overflows'¦or are we talking 'closed-loop' here?>> New plumbing was done--ball valve etc., etc., and I turned the pump on--(now don't get ahead of me, I know what you are thinking--but the ball valve WAS turned to 1/2 to start) <<Mmm'¦okay'¦>> Oh, I forgot--I installed a "Calfo Manifold" around the top of the tank in 1 inch PVC in place of the double returns already in use. <<Very nice>> I'm figuring my flow at about 3800 to 4000 gph--just from the return. <<Not with 'two 1 ¼-inch drain bulkheads' my friend (would only safely drain about 1000gph en toto). I must assume this is a closed-loop>> With the 1-inch return manifold--it has 12 outlets around the top--I can turn the valve to 3/4 open with no problem. With ½-inch reducers in the outlets, and with capped 45 degree pieces drilled with a small hole attached, I can open the valve all the way, without overflowing the tank. <<Okay, this 'must' be a true closed-loop then'¦no way you would be running this much water through your sump/through two 1 ¼-inch gravity drain lines>> I also have 2 Koralia #4--1200gph each in the rear corners. My 'buddy' at the LFS says it can never be enough flow. Is this too much flow ????? Thanks in advance, Bill Fletcher <<Well Bill, that depends much on your livestock's requirements/placement and how this flow is 'arranged' in the tank. A common rule-of-thumb for marine systems is to have a water-flow rate of at least ten-times the tank's stated volume. For your tank of course that would be 1800gph. I have heard of some hobbyists with flow rates of 50-times and more their tank's volume. I believe 'lots of flow' is very beneficial if applied properly'¦my own tank boasts more than 30-times the tank volume in water flow. I also believe the majority of hobbyists 'don't have enough' flow in their tanks. So to answer your question'¦if the animals in your system are not having their flesh blasted from them'¦if the animals in your system exhibit health and vigor, and the corals are not 'closed-up' all the time as a result of the flow'¦then no, this is not too much flow. Regards, Eric Russell>>

Re: Return Pump Flow--How Much Is Too Much? - 02/19/08 THANKS for the reply Eric. <<Happy to assist, Bill>> To start, the pump in question IS the tank return pump. On my OM 4 way, I have a DART. <<Ah, thank you for the clarification. I must say I think either there is something I have missed, or the pump is encountering a 'bunch' of headloss as there is no way two 1¼' gravity drains handling the flow volume you mention (4,000gph+)>> Each return has 6 one inch "T"s around the top of the tank, into which a 1" to 1/2 " reducer is placed, with a 45 degree PVC piece placed into that, and then capped and drilled with a small, not real small, hole drilled in the end. <<So'¦the water is returned to the tank via these small holes in the caps? Well, that would explain how the drains can handle the flow with the valve from the pump wide-open (the 'holes' are GREATLY restricting water flow)>> This allows me to swivel the 45's left or right, and raise or lower the "T"s as needed. The drain and return tank bulkheads were re-drilled to accommodate the tubing upgrades. <<Excellent'¦too bad you just didn't go a little larger on the drains [grin]>> I did forget to add/state that ALL plumbing is in the basement which is just behind the wall that the tank sits in front of. <<Cool'¦does make plumbing/dealing with some associated hassles a bit easier>> As of now, everybody--all the animals in the tank--- appear to be doing very well--I did tweak the 'nozzles' initially so as not to blast anybody--so all is well. <<Very good>> THANKS again for ALL you do for us in the hobby--where would we be without your help and knowledge. Bill <<Rewarding and encouraging to read'¦We are pleased to be of service. EricR>>

Circulation Questions. Heavy Water Flow And Fine Sand -- 01/30/08 Am in the process of putting together the components for my new 120 gallon tank (4x2x2). <<Neat>> I want to keep SPS and clams. <<Ahh'¦no 'softies?''¦excellent'¦ I don't want to utilize too much rock (75-80lbs) as I would like the tank to have an open look. <<I am much in agreement with this method of aquascaping. Far too much rock in many hobbyists' tanks in my opinion. If more biological filtration is deemed necessary a fine-grain sand bed of 4-inches or more will do the trick'¦can even be placed remotely (sump/refugium)>> I've got some unique aquascaping planned using flexible PVC. With that in mind, here is my circulation setup. Eheim 1262 (900gph) located directly beneath the tank in the cabinet for my return pump with a gate-valve to control return flow. <<Nice choice'¦good quality long-lasting pumps>> I just purchased two 6-month old Tunze 6080's (2,250gph x 2, not controllable) at a great price from a fellow member of my local reef club. <<Very nice'¦ I am a big fan of these pumps for water flow/circulation purposes. I employ seven such pumps (varying models from 1600 to 3100 GPH) in my reef display>> This gives me 5400 gph total flow. Is this going to blow my sand all over the place? <<Possibly'¦ But careful placement can mitigate this to a large extent. Regardless of what pump/methods you use, fine sand is going to 'move around some'>> Roger from Tunze said it's a matter of placement and that sugar-fine sand is going to blow around regardless. <<Ah yes'¦indeed so>> What is my best bet here? <<In what respect?>> With everything maxed out I'm looking at 45x/hour and about 40x/hour if I throttle back the return pump. I've read that this is an acceptable flow rate for a SPS system but it's the DSB that's got me worried. <<Hmm'¦ I'm moving around about 16,000gph in my display (375g 8ft tank) when everything is 'going at once,' though this isn't all the time as I have my Stream pumps set up to switch randomly. I have my pumps set high on the end-walls of the tank with magnetic mounts. I also have a 7-inch sugar-fine DSB. I do get some blowing/sand movement when flow paths meet at times, but nothing drastic. Gullies will form after some time, but this is usually gradual and can be easily repaired if/when necessary by gently raking the sand down from the high spots>> I don't like the bare bottom look. Is there another substrate that I could use that would be less likely to blow around and that would be acceptable to place clams on? <<I don't think you will be able to go much coarser before it becomes to large/sharp. It is my opinion that the benefits of the sugar-fine sand; as a biological filter, in-fauna matrix, and even a clam base, outweigh any disadvantages of movement from heavy (read that 'healthy') water flow. Regards, Eric Russell>>

Flow/Circulation 01/15/2008 <<Hello, Andrew here>> I have a 54 gallon corner reef tank with 1 built-in overflow. I currently use a Mag 7 pump submersed in a wet/dry, and 1 Maxi-Jet 900 powerhead in the tank for additional flow. I estimate that the Mag 7 circulates about 350 GPH with head loss. I was thinking of going to a Mag 9.5 which would give about 600 GPH. I also would like to remove the Maxi-Jet because of heat transfer and looks. I can never get the tank temperature below 80 degrees. My question is - what is more important, GPH circulation through sump or flow in tank? <<Flow in the tank mainly as that is where its mainly needed for the corals etc, however, overall flow through sump and also inside display tank need to be added together>> It seems that powerheads only move water around the tank and don't add to the return circulation through the overflow. It really doesn't add to the total turnover. Are powerheads really necessary if you have adequate circulation through overflow? <<Answered above. To go further, you do need to have adequate water flow actually inside the aquarium, not just via the overflow/return part of the whole reef. Flow wise, altogether, I would suggest you need to have it at around 1300 - 1350 GPH "total" water circulation, whether that be via in-tank powerheads, a closed loop or a combination of. What you have to think about, with only using flow via the return, is that if there is an issue with the sump and you have to cut it off, then you loose all flow in the display tank, hence why people will also have powerheads in the display tank and use them to achieve the correct flow>> I'd appreciate your comments. Mitch <<Thanks for the questions, A Nixon>>

Water Flow 12/31/07 Thank you for all of the excellent information you provide. Your website has been invaluable in the process of setting up my reef tank. <Thank you, great to hear!> I have a 40 gallon tank with a 17 gallon sump/DSB refugium underneath. I sized the overflow and return pump to provide close to 10X tank volume flow -- CPR CS50 overflow at 300 gph and an Eheim 1250 return pump at 317 gph -- but checked the actual flow at tank height and found it to be about 180 gph with less than 5 feet of head. <Sounds about right.> There is an EcoTech propeller pump inside the tank to provide additional flow. It is set fairly low, cycling between 200 to 600 gph, as it has the ability to turn my tank into a sand storm! <I guess so, this unit has tons of flow capacity!!> I'm thinking about putting in an Eheim 1260 to increase the flow through the sump/refugium. <Not unless you want to throttle the pump back or upgrade your overflow (perhaps drill the tank). The 1260 is a fairly strong pump and you are already at the practical limit with the ¾' bulkhead on your overflow box. Your current flow through your sump is fine.> Should I just take my wife out to dinner instead? <Yes, money well spent in all respects.> Thank you for your time and knowledge, Chris Gould <Welcome, happy reefing. Have a wonderful dinner, Scott V.>

Flow Rate 12/28/07 <Hello AJ> Hey there guys, I am running a 90 gallon reef tank, mostly SPS, but there are some LPS and some soft corals. I was looking to get some advice on my flow rate, I am currently running a Mag drive 1800 in my sump, which from looking at the diagram with a pumping height of about 4' gives a flow rate of about 1375 gph, which is then going to a squid which has two outputs on each side. Along with that I have two Hydor Koralia 4's one on each side of the tank facing towards the top of the tank, and are wired to the Koralia's pulsing wavemaker. According to my calculations this gives me a flow rate of about 3775 gph, which is about a 42x per hour turnover rate. I don't know how much more flow SPS require in order to thrive, but from everything else I have read the average turnover rate is about 10-20 x per hour. So is this overkill for my tank, should I downgrade to the Hydor Koralia 1 or the Hydor Koralia Nano which would give me a turnover rate between 24-21, or should I just ditch the Hydro Koralia's all together which would give me a turnover rate of ~15. I can clearly say some of my LPS have been suffering from this much flow, but my SPS are doing great, do you think my SPS would get the same success out of lower turnover rate of about 20x per hour. Not to mention, while some of my fish have gotten used to this much flow, some other spend very little time in the open. What do you think? AJ <I would not reduce the flow but rather redirect it. Make sure that the pumps are not directly aimed at the polyps of your LPS. The Koralia 4's are definitely the best option for your system. They move a lot of water but do not focus a forced stream. If your pumps have the new "flow concentrator nozzles" on them try removing them and see what happens. These nozzles are a black ring that snaps on the end of the pump. If your pump did not come with these "add-ons" then disregard. The turn over rate you have established will do much to benefit the system overall. It takes some experimentation with coral placement and pump flow direction to achieve the harmony you seek. Try a couple of different things and see how it goes. Rich-aka-Mr. Firemouth>

Flow in Reef Systems -- Video 12/19/2007 Hi, Crew. <Hi Dan, Mich here.> I often hear posts about "how much flow" for reef systems. I've had the honor of diving some real reefs, <You are lucky indeed!> and can attest to the flow levels. <Yes, the water movement can be quite incredible.> Here is one in North Sulawesi. <Ah, a very nice place!> Note that we were swimming against the current for a lot of the time! <Kick! Kick! Kick!> Sorry for the somewhat clumsy camera work, there was much to look out for (hate to hit one of those soft corals going several knots!). <Or even worse one of the hard corals!> For those who question your 20x/hr recommendations, point them this way :) <Thank you for sharing.> http://www.youtube.com/watch?v=cxpoO0MnQuw Enjoy, <Wish I and some of my fellow crew members had been there diving with you! Cheers, Mich> Dan

Flow... Reef circ.    9/4/07 I am running a 120g 48x24x24 reef tank, with about 150lbs of Live Rock. I am looking at 3 maxi-get 1200 powerheads which have 295gph each, and a controller for it, with 2 rotating in opposites and a third on a separate timer. Along with my 800gph from my little giant should that be enough flow? <It totally depends on the arrangement of the tank and what kinds of coral you want to keep. It's probably sufficient for corals that need less flow, but probably not enough for Acropora types. But again, it will depend on the arrangement of the pumps and the rock. Keep the live rock off of the walls of the tank to maximize flow (that will help). Best, Sara M.>

Re: Flow, reef, circ.   9/5/07 Yes the rock is positioned at least 5-6" away from the glass at all times. <excellent> The complication in the tank is that there are two overflows ( not corner placed) so there is sort of a challenge to stop dead space between the two overflows and the rock, since the effective distance from the outer edge of the overflow to the rock at times is small around 2". I picked up a Tunze 1200gph powerhead, I like the output it is very strong but very broad, so it makes alot of water movement without putting any super high movement areas in front of it. <Ah yes, these are great. I also have one and I absolutely love it.> Would two of those Tunze 1200gph powerhead seem reasonable for the tank, they would be aimed from the two upper back corners down towards the center of the front of the tank where they would collide and create turbulence... <This sounds like a good idea to me. Another nice thing about the Tunzes is that the flow is so bulky that you don't get as much turbulence when you point them at the same spot. But turbulence is ok (actually preferred for some corals) so long as it doesn't constantly cause sand storms.> with possibly one or two of my old 250gph powerheads hidden in between the two overflows to prevent a dead space in that area? <Sounds like a plan... when it comes to water flow, more is almost always better than less. Seriously, short of putting a fire hose in your tank, it would be quite difficult to have too much flow.> Thanks again for your continued patience with me <no bother at all :) > Josh <Best, Sara M.>

Stable water temperature? SW speculations on a return from HI snorkeling... Aloha Mr. Fenner! <Howdy!> I just got back from the Big Island and Kauai, where I spent ten days snorkeling to my heart's content. <Bet you have a nice tan!> I want to ask you a question that's been on my mind for some time. I have read, over and over again, on this site and in your book how important it is to keep the water in one's aquarium at a stable temperature, and that stability is more important than achieving a specific temp. <Mmm, yes> The reason given is that the enormous ocean environment provides a stable temperature, which our livestock is inherently accustomed to. <Agreed> So, on to my question: I have noticed in years past, and again on my recent trip, that when I snorkel, I encounter patches of colder water, and then patches of warmer water, in the same general area, while I'm observing species that I have in my tank at home. What do you think? <You are certainly correct... Particularly on the Big Island, there are zones where much cooler freshwater is intruding from "Pukas" and cracks in the rock... having traveled from higher elevations... this presents a difference in osmotic pressure and density as well as a varying thermal regime... Yet the life there appears healthy to me> Are these temp differences I notice more subtle than I realize? <I believe so... Maybe one way of putting this situation in perspective is to realize that the motile animals (do note the difference in species make-up and abundance in these areas in the way of not-so motile and attached biota) do move in/out of such zones (near the land, surface)... and that they are in good shape to begin with... and I'd speculate that the mixing in these areas is to their advantage in avoiding predation...> I have been very curious about this, as I do struggle to keep a stable temp in my tank in my south florida home, especially in winter months. By the way, I was struck by the incredibly strong currents in the ocean! <Heeeee! More than Tunze and Hydor powerheads?!> I have four power heads in my 130 gallon, and I fear they are woefully inadequate! <Ah, yes... a useful lesson> I appreciate whatever comments you have to make, and continue to enjoy and learn from this site, so thanks! Elise <Thank you for sharing... I do think "constancy" is an important aspect of our successfully maintaining a small part of a captive sea... but it is only one area of concern/influence. Cheers and a hu'i hou! Bob Fenner>

Plumbing a Mag-5 Pump and Calculating Head-Height -- 03/05/07 WWM- <<Adam>> I have a 65g. AGA tank with built in overflow rated at 600gph, <<Mmm...a single 1" drain likely...600 gph is "optimistic" and downright problematic...in my estimation>> and a Mag5 return pump. <<A decent enough make of pump>> The Mag5 is rated at 500gph, and 310gph at 4ft. <<Yes>> Is head-height determined by total distance between pump outlet and tank return outlet or simply height from return pump to top of tank? <<Is a bit more 'involved' than either statement.  Head-height/head-loss is figured based on a combination of factors to include length of horizontal and vertical pipe runs (though these are not 'calculated' the same...I'll explain in a moment), plus the type and number of ells/tees/fittings/et al, and even the diameter of the pipe/tubing used.  Calculating vertical pipe/tubing installations is simple...one foot of rise equals one-foot of head-height, and it is generally universally agreed that every ten-foot run of horizontal pipe is equal to a one-foot rise, as is each 90-degree ell and each tee fitting in the run.  So, as an example...if you have a return line that rises two feet above the pump, makes a 90-degree turn, runs horizontally for 5-feet, makes another 90-degree turn, rises another two feet in to the tank, and terminates in a tee...you are imposing a resistance on the pump roughly equal to 7 ½-feet of head-height.  Does this make sense to you?  As for the diameter of the pipe/tubing, it is often advised to match pipe-tubing diameter to the output diameter of the pump...but in my experience; especially with the Mag-Drive pumps, I have found that 'upsizing' the pipe often yields better results/flow rates.  For the pumps with ¾' outputs and smaller, I have found 1' pipe/tubing to work very well>> Is this pump vastly underpowered for my setup? <<That depends on what you want the pump to do.  If the only purpose is for filtration/processing water through your sump and your head-height is equal to 4-feet providing 300 gph of flow then yes, I would consider this about ideal for a single 1' drain>> It seems a fine line between maximizing overflow flow capacity and overflowing the tank. <<Yes indeed...and that's even assuming the accompanying noise/surge aren't an issue>> If so what would you recommend?  I am in the process of converting from Wet/dry to sump, so many possibilities.   <<My recommendation would be to utilize a pump that; based on your plumbing configuration, provides about 300-350 gph to the sump...and utilize powerheads/closed-loop/etc for additional flow within the display tank>> Thanks for all the help! <<Happy to share.  Eric Russell>>      

Tank Flow Calculation Questions - 2/20/07 Greetings gang, <Hey Bob, JustinN with you today.> I am finalizing plans for a new tank and refugium (with lots of help from your wonderful site) and I have a general question about recommended GPH in the display tank. <Ok, lets see if I can't help clear it up some.> Should you subtract the 6 inches for the DSB when calculating the total gallons of the main tank? <I wouldn't> What about the space that the live rock occupies? <Again, I wouldn't personally.> Thanks for all your help, Bob <I'm a big proponent of heavy flow in marine settings, myself. This is not to mean you want things so turbulent that corals would seem to lean solid to one side, but instead allow for a good amount (I would aim for 15-20x the tank volume, considering my statements above as well) of diffuse flow. Hope this helps clear things up a bit for you! -JustinN> Power Heads  - 1/22/07 Hello, <Hey Ron, JustinN with you today.> Could you tell me if there is a formula for deciding the amount of GPH power head to use in a tank? <Typically, the "rule of thumb" for lower flow requirement corals, and a FOWLR aquarium is to aim for turnover at a rate of 10 times the tank volume. For example, a 50 gallon tank's 'minimum flow requirements' would be a turnover of around 500 gallons per hour.> I would eventually like to get some soft corals in a 75 gallon tank. I was looking at an Seio 1100 GPH power head, does that seem ok or too much movement for that size tank. <I would likely go for a pair, one per side of the aquarium.> thank you for your help. Ron <No problem, Ron. Glad to help! -JustinN> Re: Power Heads  - 1/22/07 Thank you for the quick response, if I put a pair do I need to use two 1100 GPH units or can I go a little smaller say 620GPH. I'm thinking in terms of generating less heat in the tank. <The heat will likely be of little concern with only 2 pumps, in a tank this size, my friend. However, you would likely be ok with 2 of the smaller units. The choice is yours, though I don't feel the heat concern is warranted. Good luck! -JustinN> Plumbing/Water Flow In A Three-Sided Tank - 01/09/07 WWM crew, <<Howdy Brian!>> Got the Reef Invert book by Anthony and Bob and have been masticating on its colorful fibers. <<Hee-hee!  But wouldn't a piece of gum be better?!>> Planning a system with upstream refugium, display, and downstream sump/fuge with return. <<Cool!>> I want the display to be viewable from both sides and along the width, more like a biotope than the standard, two dimensional wall reef. <<I see>> I am thinking 20" tall, 24" deep, 60" long acrylic (125). <<Ok>>    I am having trouble imagining how plumbing might be incorporated to avoid obstructing the view. <<Will have to be run in/out from the "concealed" end>> Can I have symmetrical overflow, like reef-ready tanks but on the one 24" width which will face the wall to keep pipe out of view? <<Sure, you might even want to consider a horizontal overflow, or just bulkheads with screens...though the latter requires a bit more fuss to mange water levels/flow.  Whichever method you choose, don't worry about the plumbing outside the tank on the end being visible.  This was a concern for me when I installed my current system a few years back (in-wall system viewable from both sides), but once there is water in the tank the light refraction prevents you from seeing through the end panel>> Will this be inviting dead spots on the far side? <<Assuming flow will only be coming from the one end, you will need a full flow pattern, and in my opinion, preferably something that pulses/alternates intensity.  A Tunze Wavebox would be ideal here I think, though if you don't want to give up the space associated re you could also get by with a pair of Tunze 6000 pumps mounted to/below the overflow and cycled with the Tunze 7095 controller>> BTW, I am thinking 1500 GPH flow rate for the display, <<I don't think this will be enough, especially considering the configuration.  The Tunze pumps mentioned when combined will give you a bit more than twice this (when "both" pumps are at "maximum") and I think you will find this to be a big help at keeping detritus in suspension at the far end of the tank>> 1000 GPH for the up-'fuge (16x24x60) -- 'pod colony. <<Should be ok, but if you find the flow a bit much to manage here you can easily reduce by half and still be fine>> As always, thanks so much. Brian <<A pleasure to share, EricR>>

To Flow or not to flow 9/13/04 Hello to the WetWebMedia Crew! <cheers :)> You have been so helpful with all the other little bumps I have hit I decided you would be the first people I ask for a recommendation on flow improvement. I have an 80 gallon AGA 48"X18"X21"tall and I am upgrading it to handle SPS.  I currently run a MAK4 (1120 GPH-head loss-SCWD loss=?) from my sump to a SCWD (squid) up to two sets of Loc line jets on each side of the tank.  The flow was fine for softies but I worry it will not be enough to keep my SPS happy.   <agreed... garden reefs need about 10-20X water flow... but SPS tanks generally need a minimum of 20X. So... your 80 gallon tank needs at least 1600 gph... closer to 2000 gall would be nice> I have considered a spray bar but have heard stories of frequent cleanings and increased backpressure leading to burst return pipes.   <true> I was wondering What you would recommend to boost/maximize my flow?    <please do check out: http://wetwebmedia.com/pbh2oret.htm> Do you recommend Sea Swirls?   <yes... they are very fine products> If I could avoid another couple hundred dollars in pumps that would be sweet as my new hood broke the bank!  Any suggestions would be much appreciated! <the above link is a very inexpensive and effective means of delivering water flow. Best regards, Anthony>

Flow rate Is flow rate of a tank determined by the return pump? <To the largest extent, yes> I know that in order to keep the sump at a certain level, the drain line to the sump has to be larger than the return line, for example, a 1" drain with a 3/4" return. <Yes> | If this is true, does installing a pump with a larger flow rate increase the flow rate of the aquarium? <Can, should, yes> What is the recommended turnover rates for different types of aquarium setups? <As a general "rule of thumb", more is better... ten, twenty times turnover for most all> Thanks for the info. I am getting tired of working in my trade. It has become very stressful and I do not enjoy it anymore. <Very sorry to hear... but glad to realize that your awareness> For the past 7 years I have been gratified with my aquariums and have been doing much research online with things pertaining to this hobby. In the past year I have been thinking of performing a slow (a little at a time) change in career to designing  and constructing acrylic aquariums, refugiums, wet/dry filters and terrariums. I  know I can do it and I know I would love it. <Outstanding. Welcome to our trade. Bob Fenner> How much water flow for a 72 gal? Adam! Thanks for your response. By 20L, I meant a 20 gallon long aquarium. Sorry for the confusion. << Okay, that sounds better. >> Since then space constraints have limited me to a 15g refugium. Isn't 800gph in a 15 gallon refugium too much? Shouldn't I keep the flow low? << Well you don't want the water blowing all your algae around in your sump.  But on the other hand the refugium only helps out because it is connected to the main tank.  So to get benefits from it you need that water turning over. >> BTW, I just ordered a Tunze stream 1600gph pump. I'm planning to have two Seio 620s on one end and the Tunze at the other -1600gph meeting 1200gph somewhere near the middle of the tank. The Tunze has a 2" outlet, and the Seio's 1.5" outlets. As a result the output velocities will be close. I could use the Mag3 from the Remora Pro to pump water from the refugium to the display. With a 4' head it's good for at least 200gph, and the skimmer can be powered by a Quiet one 3000 rated at 780gph. << Sounds good. >> I hear these pumps don't like back-pressure and tend to overheat. Any truth to that? << All pumps have that problem, but if you are restricting the output and not the input I think you'll be fine. >> This will result in a total flow of about 3600gph for a 72G. Is that too much for just Xenia and Capnella? And the fish? I worry about the clown... << You can never have too much flow. This sounds great. >> Thank You for your time! Narayan <<  Blundell  >> Water Movement For Acropora Hello, <Hi there! Scott F. here today!> Do Acroporas do better with a direct flow of one power head or with 2 - 125gph Power Sweep power heads? I have a 10 gall nano reef tank with 1 Acro with plenty of room for more! What do you guys think? Thanks for your time! <Well, most of the Acropora that favor high flow will benefit from randomized, indirect flow. Laminar flow directly into a coral can literally peel the tissue right off of the colony. Better to use those Power Sweep powerheads, or even some sort of rotating return device, like the wonderful Sea Swirls! HTH! Regards, Scott F.> Skimmer flow Bob- could you tell me if a protein skimmer water movement adds to the flow rate of the reef tank. The skimmer is out side the sump with a external pump 700 gph.         RGibson <I'd say yes... and would like to add a proviso... that there is MUCH more flow in the wild in most all settings than anything a hobbyist supplies... Practically speaking, w/o sucking up or blasting your livestock against a tank wall, there is no such thing as "too much" water flow. Bob Fenner>

GPH question.. 2/2/04  What gph rating do you recommend for a 180 gallon tank? I'm going to have it "T" off to both returns from my sump, so its going to be one pump doing all the work. I plan on going with an Iwaki, and they have one rated for 1500 gph and 2000 gph @ 4ft. Any good advice will be greatly appreciated...  <As a general rule, total water flow should be 5x the tank volume for a fish only tank, and 5-10x or more for a reef tank. The problem you may encounter is weather your drains will handle such high flow. You may have to choose a smaller return pump, which has other advantages such as less noise, less power consumption, and lower cost. You can make up the difference with powerheads or closed loop circulation. Hope this helps. Adam>

- Too Much Turnover? - Bob, <JasonC here in his stead...> I am having a slight problem with a recent ocellaris clownfish I just purchased, he seem to have a difficult time swimming in my tank with the current. Do I have too much turnover? This is what I have as of now: 2 maxi 900s - 230 gph = 460gph 1 penguin bio wheel = 330gph for a total of 790gph. I have a 46g bow front with 50# of Fiji live rock. that is a turnover of right around 17.1x an hour. but my major questions are will the clown be ok? <I think so... give it some time to 'get in shape' as it were...> looks like he is struggling at times. <Some of that is just due to the way they swim... seem to be struggling but in fact they are not.> great color to him, he is eating. Will I be ok if I turn my BioWheel off until I get my skimmer? <Uhh... I wouldn't, think this does provide some of your biological filtration... would leave it running.> When I get my skimmer I plan on taking the BioWheel off the tank anyways. will my live rock be enough filtration for now until I get my skimmer? <Perhaps, but not something that I like to see happen suddenly... perhaps take the wheel itself out and let sit submerged inside the tank somewhere in case you need to get it running again soon.> thanks Tim <Cheers, J -- >

- Circulation Question - Hi Folks:  Thanks for all the great info on your site. I'm new to the hobby and have been voraciously reading your words of wisdom. I have a 58 gallon FOWLR that is 8 weeks old, filled with 50lbs of live rock and 4 fish (2 YT Damsels, 1 Clown, and 1 Yellow Tang).  I have a 20 gallon refugium underneath with a Mag 2 pumping 125gps back into the tank (when factoring in the height.)  This week 2 fish died with what looked like tail rot and I'm concerned that a purplish algae growing on the rocks and sand is Cyanobacteria.  I've been feeding with a pinch of flakes in the morning and 1 cube of frozen food at night, but have now backed off to 1/2 cube at night. After reading your many articles on circulation, I've realized that my circulation is woefully inadequate and may be the source of my problem, so I added a Maxi-jet 1200, pumping 295gph.  I am also considering changing my refugium pump to a Mag 7 as advised by my LFS, which would pump 480gph at the given height. <Hmm... or just some more circulation in the tank... would allow the refugium to stay more of a refuge than a sump if you left the pump you had. You could easily get two more of those MaxiJets in there.> I am concerned that I am overdoing it on the circulation. <Nah...> Since I added the Maxi-jet, the fish are now hiding in rocks and caves and only come out at feeding time. <Could be for other reasons, but give them some time... I think you will see the fish actually like it. Am circulating roughly 1800 GPH in my 55 not including the return... should be no big deal.> Should I replace the 1200 with a lower powered model, or is this just normal behavior where the fish just need time to get used to the increased circulation? <It's a bit of a surprise at first, I think... but they should adapt to it pretty quickly.> Thanks, Ken <Cheers, J -- >

Water Turnover Hello all, wow it seems like you guys are getting more and more questions every day!!! My question is about water turnover. I read that water turnover for a reef tank should be between 15-20x. I just wanted to be clear that what is meant by turnover can include powerheads so if I am running 2 powerheads, 1 @ 175gph 1 300gph and a protein skimmer that has a powerhead that runs @ 295 gph for a total of 770 gph in a 46 gallon tank I would satisfy that requirement. I just wasn't clear that what is meant by "turnover" only meant a sump system where the water was leaving the tank and returning. <Cumulative, all movement in the tank, so your figures are correct. Although, you may have to add movement to a 'spot' to help with algae/detritus control, Don> Thank You. Angelo

Closed Loop Flow rate I did go to RC and enter the params... all it said for a result was that I have 7 feet of head pressure.  They even broke it down to 6 feet from the 90-degree elbows and 1 foot of actual height.  But this would imply no flow for my system. <If you have flow, there must be one or more of several things happening: Actual head height is not as much as assumed, pump output is greater then assumed, less actual plumbing restriction than assumed.> Side question: I have the pump submerged in the tank about 1 foot below water level, then water goes out over the rim of the tank, down about 8" to accommodate the SQWD and then back up over the rim and into the tank.  Should I consider any head pressure from this arrangement from the 1 foot up (assuming the 8" up and down will cancel out) or does it just have to do with the water level in the tank (i.e. about 2" of head to get over the rim of the tank)? <Actual head height would be less than 10" as the 8" doesn't  "cancel out", but it isn't a straight 8" head either. Pump depth and only pushing 2" over rim also changes equation in pumps favor.> If I don't need to include this in the calculations then I come out at about 6 feet of head pressure, and the pump is rated around 320 g.p.h. at that point... that would explain it.  Although it seems like more flow than that... it's really hard to tell. Jeremy <There you go. Hard to judge from there without a flow meter.  Craig>

Too much water flow? <Hello again Luke, PF here with you tonight> I'm wondering... is it possible to have too fast water flow in the tank? I currently have 2x 150 power heads in 20gallon tank. The water is pretty agitated. <Well, you're turning over the tanks volume 15 times an hour, no surprise there> I have 2 small clownfish in there. Could the water current be too strong for the fish? I currently have no corals in the tank. <Well, unless the fish are being dashed about on the rocks, or are always struggling, I wouldn't worry to much. You can always swap them out for something with less power if you're really worried.> Thank you, Luke <You're welcome, have a good evening, PF> - Flow Rates - <Good morning, JasonC here...> I have enjoyed reading all the post and helpful answers as well as Bob Fenner's recent book.  I have a question about plumbing a 65 gallon reef tank.  First how can you determine the drainage capacity of a particular size bulkhead? <Somewhere, there is a formula but for the life of me I can't recall at the moment - if I recall, 1" is capable of 600 GPH, so 1.5" will be much more so.> I am thinking about using two 1.5" overflows in the upper back wall in one corner approximately 3" apart and enclosing them in a full size (tank depth) overflow box to increase surface skimming capacity.  The box would fill and then empty via the 2-1.5" overflows into the sump.  Does this sound feasible? <Sure.> From the sump inlet side I want to feed the skimmer then into the clean side and back to the tank via one pump.  Also from the sump inlet side I want to go directly back to the tank with one pump and split into two returns for basically a closed loop circulation as I would rather not use powerheads.  How does this sound. <Feasible, but you might want to at least feed the skimmer and closed loop from a settling chamber in the sump - water coming from the tank will have a lot of air in it which will make the pumps cavitate and in turn be less efficient and noisy to boot.> One of the most confusing parts of setting up my first reef tank is the plumbing to provide adequate flow and circulation. <I think you are on the right track.> Thank you very much for any advise. John <Cheers, J -- >

Water flow question I am currently setting up a 300g L.R. and aggressive fish tank. I have been keeping tabs on your Q&A section and have noticed a lot of reference to water movement. Now I find myself questioning my own set up. Here is a rundown on what I have planned so am just wondering if my flow will be adequate; 4 hundred lbs rock, to 8 in sand,55g sump with circulation disrupters (pc.s of acrylic sideways) chiller of course, second 55g sump with app.2 mangroves and mud bottom with app.900gph flow, the main tank will have 4200gph return flow with 4 additional 700gph wave generators inside to make sure of no dead zones. Does this sound adequate or should I even shoot higher. PS. AND YES THERE WILL BE TWO SKIMMERS DOWN FLOW OF THE MANGROVES. Mahalo from Maui Bill <Aloha, Bill! It sounds like the water flow in the display will likely be quite fine. The old recommendation of 4 to 10X tank volume is dead. Modern aquaria with large live rockscape if nothing else negate that. 10X per hour is a minimum... reefers and tanks with aggressive/messy feeding fishes like your should be closer to 20X of random turbulent flow. The only thing I would do different here is lose the wave generators. Run straight flow in a random turbulent pattern... Far more effective. The bottom line is that we want no dead spots for detritus to accumulate... all should be kept in suspension for skimmers, etc. No worries here about excessive flow as long as linear/laminar movement (one-directional) is avoided. Further info here: http://www.wetwebmedia.com/circmarart.htm Best regards, Anthony>

Water flow I am currently setting up a 300g L.R. and aggressive fish tank. I have been keeping tabs on your Q&A section and have noticed a lot of reference to water movement. Now I find myself questioning my own set up. Here is a rundown on what I have planned so I'm just wondering if my flow will be adequate: 400 lbs LR <Great!>,to 8 in sand <Do you mean 8 inches of sand? IMO this is too much for a FOWLR tank. Have a thin bed an inch or less and you won't need to worry about it becoming a nutrient sink. Nitrates are not that big of a concern for your tank...nitrates are totally undesirable in a reef tank.> 55g sump with circulation disrupters <For this size tank, I would want a bigger sump. Many people like the sump to be around 30% of the tank volume. This would put the sump at about 90-100 gallons. This will add flexibility to your tank and make overflow of water onto the floor much less of a possibility.> pieces of acrylic turned sideways <called baffles> chiller of course <Is there a specific reason for this addition? In reef tanks, chillers are needed because the intensive lighting produces lots of heat that raises the temperature of the water. You will not want intensive light for this setup because of high nutrients from messy feeders, etc. Intensive light for this type of setup will most likely cause a hair algae nightmare.> second 55g sump <55g + 55g=110 g. The two sumps will be adequate. The second sump like the one you are describing is commonly called a refugium.> with app.2 mangroves and mud bottom with app.900gph flow <You will need much less flow through the refugium. A refugium is a place with gentle currents.> the main tank will have 4200gph <Acceptable> return flow with 4 additional 700gph wave generators inside to make sure of no dead zones. <Okay> Does this sound adequate or should I even shoot higher? <Sounds good. No complaints from me.> PS. AND YES THERE WILL BE TWO SKIMMERS DOWN FLOW OF THE MANGROVES. <Fantastic! Don't skimp on the skimmers! Spend some of the money your going to save from not buying the chiller and buy really good skimmers like Euro-reef or similar brand. With aggressive fish (big, messy eaters) you're going to need the best filtration possible.> Mahalo from Maui, Bill <You're welcome! Please peruse the WetWebMedia website for this and much more information about saltwater aquariums. Knowledge is power! David D. in sunny Las Vegas.

Water Flow Rates Dear WWM, I kept marine fish in the 60's and early 70's and am currently in the process of "getting up to speed" in preparation for a reef tank.  I have spent much of this prep-time on your very helpful web site and am looking forward to your new book. <I can tell you the guys are ready to finish it too!> My question(s) have to do with figuring out water flow rates.  I have not purchased any equipment yet, just doing a lot of reading. <Very good!> If (for this example) I had a 110 gal tank and am planning on a back drilled overflow arrangement using 1" ID PVC.  From what I have read it appears that one could estimate 600 GPH (per hole) to be gravity fed to the sump. My sump will be 22 gal. capacity, sitting 4 feet under the surface of the show tank.  The skimmer will be in the sump with it's own pump. <Ideally the sump should be 1/3 the tank volume. Much water to account for....> If I want say 12 times the capacity of my tank to flow through the sump and back to the display tank. 110 gal x 12= 1320 GPH. Should I drill (3) 1" ID holes for my overflow (1800,GPH) and use gate valves above the sump to adjust the overflow rate into the sump? <The reverse of this. Unrestricted overflows from display to sump, valve on pump (sized as you suspect) to control flow rate to display.> Put simply, is it only a matter of selecting the right return pump (factoring in head pressure etc) to match the overflow rate from the display tank?  (I have visions of my sump looking like a swirling mass of water rushing through, sweeping sand and LR all around)! <Yes.  Use a partition or small plastic bucket/pvc fittings to control the currents. It is best to oversize the overflows like crazy (If they call for 1" I use 1 1/2").  The flow rate is controlled with a simple PVC gate valve directly behind (inline) with your pump, sized to account for head height, plumbing restrictions, etc. There are no valves on the overflows, they flow freely by gravity to a section of the sump and perhaps filter bags.  I have my doubts if 1" pipe will carry 600gph passively (gravity fed). I advise over sizing overflows/bulkheads if at all possible or using more than anticipated.  Also, purchase bulkheads first, they require larger holes than the pipe ID, drilled with a hole saw.> I know I also need to position my overflow near the surface.  What "formula" do I use to figure out how many gallons will go down the overflow (based on the height position or actual water intake level of the overflow)  in the event of a power failure? i.e.. a 1.5" drop in the water level of a tank that is 48"x24"x 25" will work out to be "X" number of gallons draining into my sump. <You don't. You put the top of the overflow 1/4-1/2" below the water level you want to maintain in the display (making them adjustable is a good idea) fill the tank to the top of the overflows and then fill your sump, leaving a little room just in case. MAKE SURE THERE ARE SMALL 3/16" HOLES DRILLED IN THE RETURN LINES (the pumped line from the sump to the display) JUST BELOW THE SURFACE OF THE WATER of the display (the level desired in the display while running) which would be the same level as the top of the overflows. These will allow air in to break the siphon in the pump/return line as the water level falls so the tank doesn't siphon the tank to the bottom of the return lines, but stops at the top of the overflows. If the power goes out now, the water will only refill the sump to the original non-running fill level.> One last question, for now.  What is the ideal water level in a sump (more specifically, in a 22 gal. sump should I keep it approximately 1/2 full, 3/4 full etc leaving some, yet to be determined room, for the overflow in the case of power failure)? <Fill as above. If care is taken to stop siphoning below the overflow level, the sump can be filled say 3/4 or slightly more when the system is not running. When it is turned on it will use more water in the system, but can only return to the former, non-running level, not overflow. Does this make sense to you? It's important you understand.> Thank you much for your time and interesting reading. (This is not something that was a possible 30 years ago when I first started out, and now to have such a resource at my finger tips...it's great!)  Thanks again, Cary <You very welcome Cary, have fun!  Craig>

Pump Up The Volume! Hi and thanks for the quick response.  I'm almost finished with my setup, but could use some clarification on 2 things: My pump can put more water into the tank than the overflow can keep up with. I have a valve I can turn down to slow the pump: is that bad and will it overheat the pump by keeping this back pressure on it? <Should not put excessive back pressure on the pump in a well-designed system> I was also thinking of increasing the rate the water is drawn out of the tank by adding a straight siphon from the inside overflow box directly to the sump.  This siphon will still break if the power goes out, but won't start up again (like the U tube), so I would get a switch that won't turn back on after a power outage.  Is this a dumb idea? :) <I don't think it's a dumb idea. Actually, since the straight pipe doesn't rely on siphon, it will actually restart when the pump pushes enough water to reach the top of the overflow. Personally, I think that this type of standpipe is much more reliable than an elbow> How do other people balance the outtake with the pump power, besides adding more overflows or having less powerful pumps. <I've seen people knock out skimmer box teeth to allow more water in, adding larger standpipes in the overflow to the sumps, etc. Lots of good ways for creative people to accomplish this. Do use the wetwebmedia.com chat forum, where you can connect with lots of other DIYer's.> My Ebo Jager heaters say not to immerse beyond the indicated water line, but I know that some people still completely submerse them (horizontally) anyway.  Is that risky? <Nope. Most people with sumps seem to use them in a horizontal position. By the way, the line on the Ebo's refers to the minimum water level that the heater should be immersed in when in a vertical position. Should be no problem horizontally> Thanks again! Mike <And thank you for stopping by! Good luck with your setup! Regards, Scott F>

Water Movement Thank you for all the help received so far. <You're welcome!> When considering water movement, what counts as low, medium and high? <IMO anything under 10x per hour is very low. Anything over 20x is very high. Anything in between is just about right unless you have an SPS tank> In a 36 by 12 by 15 inches tank I have two Fluval plus 2 filters running all the time, one with coral gravel and the other with Cerapore. The filter containing Cerapore provides the most water movement. In addition I sometimes use a third Fluval plus 2 which contains PolyFilter and Rowa phos. With all three going, the seaweed sways gently. What water movement is this? <Low> What animals appreciate it? <Many including mushrooms and bottom-dwelling fish> Also I have a pearl bubble coral, Physogyra. This coral seems to be doing ok, but I have heard conflicting reports of correct water movement and light. <Low to moderate current. Please feed this critter> The coral is just more than half way from the top of the water and the metal halide is around 16 inches above the water. <Might be better off in the lower level of your tank. It doesn't need really strong light. In fact, it may not fully expand in the presence of really strong light. David Dowless> If it helps, the coral was green but has had sufficient light to turn brown. I don't know the type of bulb is in the metal halide.

Circulation for 840g Hey Guys, <Hello!> Thanks for taking your time to read this and hopefully answer a couple of questions for me.  I'm working on the set up of a 840 gallon aquarium <Fish Only?> and was wondering about circulation.  I am considering using the Dolphin 5600 which as I understand is rated at 5600gph at eight foot head, the returns will be at a height of 7 ft. (the tank is 7'X4'X4' and the stand is 3' tall), I know this will only turn over the tank about 6.6 times per hour, will this be o.k.?   <Maybe...as a bare minimum. I would want more circulation. Be sure that your overflows are large enough to handle the volume that you want to push through it. Otherwise, pump size won't matter. You have three options for increasing circulation: use powerheads (a dreadful idea), larger pump (not bad) or a closed loop circulation system (YeeHaw!) This is what I would do. A closed loop circulation system will require an additional pump but it really is the best idea. Plans for doing this abound on the internet. I want to suggest Anthony Calfo's book on Coral Propagation. Circulation will help you avoid algae and Cyanobacteria problems as well as contributing to the overall health of your tank. The fish will love the added water movement. Remember, these critters are coming from the ocean>   I am really open to any other recommendations you could make on other pumps, but at the time I would like to use just one strong pump, and add smaller ones when finances allow.  Any other pumps you would rather use? <A dolphin will do the job. When you need this much circulation, your choices are somewhat limited. Just be sure it is saltwater safe> The second and third questions concern the plumbing.  The pump has 2" in/out-takes and I was planning on t-ing the return into 2 2" returns, one for each side of the tank, ( the tank is going to be viewed from the two long sides and one short), does this sound o.k.?  Any suggestions? <I would want more returns within the tank. You will have very little circulation with only two returns. I would want the largest returns that I could find. You may even need to special order the parts. Only 2 returns at 2" a piece is too few and too small. Plus, there's no way over 5000 gph will go through a 2 inch hole> Lastly, the drains in the overflow, I am planning to use 2" bulkheads but am not really sure how many should suffice, 3, 4, 5?   <The more the merrier. For sure, at the very least one on each end and one in the middle. I would probably do 4 large bulkheads (as big as possible) spacing them evenly across the back of the tank. If noise becomes a problem, build a Durso standpipe...It will make the overflows silent> Like I said, I am planning on adding at least one more circulation pump (2-3000gph) in the future so I guess I'm asking how many I should use for 8-9000gph turnover. <That would be fabulous for the closed-loop plumbing that I was talking about. Do yourself a favor and get the Calfo book>   Thanks for your time, and best wishes to all. <It's my pleasure> Carl P.S.---Your website is a great resource to the hobby. <Thanks. David Dowless>

Re: Current Thanks for your help so far....this is the best site I have found for information on marine tanks.  I have a quick, easy question.  It's about current in the tank, and how much water current is sufficient.  First I'll explain what I have thus far. The tank is 90 gallons.  48X24X18 (standard 90 gallon tank)  I have a mountain as I call it of live rock in the center of the tank, gradually leveling out to the sides.  All the rock is doing very well.  I'm still cycling my tank with the rock, 2 cheap domino damsels, <don't tell them that.> a convict blenny, and about 10-15 hermit crabs.  The water testing levels are all in check thus far.  Now for the water current dilemma. I have a FLUVAL 404 canister filter that shoots current from one corner, I have my protein skimmer causing a waterfall type current on the other side of the tank.  In the center, I have a powerhead shooting current downward over the rock towards the front of the tank.  Both powerheads are moving about 295 gph and the Fluval is slightly more.  Is this too much current for the live rock in the tank? The fish seem to enjoy it but I don't want to harm my rock. <Fear not, they are tough> I have been told that the more current the better, but I just want to get a second opinion.  Also, would too much current harm the fish?  Eventually I hope to get a wave maker with several powerheads that change throughout the days.  Any information would be greatly appreciated.  Thanks in advance.  Happy holidays also. John <Thank you, happy Holidays to you as well my friend.  May your holidays be filled with tanks, skimmers, sterilizers, rock, sand, fish, and all that fun stuff.  The more flow the better is correct, but there are different kinds of flow.  Save your money on the wave maker and check out the article below. http://www.wetwebmedia.com/circmarart.htm Best Regards, Gage>

Powerheads Bob, a question about powerheads. <<Bob's not here, man. You get JasonC in his stead.>> I 46 gallon bow front marine tank. I have a Aqua Clear 300 on one side of the tank and I also have a Aqua Clear 400 on the other side of the tank. My ecosystem also has a Rio 600. The powerheads face each other to get a turbulence kind of effect and the Rio just agitates the surface. Do I need additional powerheads because of the bow front? <<I wouldn't think so - this seems like adequate circulation, but time will tell. If you find yourself fighting problem algae, then perhaps you might consider an additional powerhead.>> Thanks <<You are welcome. Cheers, J -- >>

Re: Porcupine Puffer (actually water movement, pH: marine) Anthony: Thanks for the help. 2 more follow ups. 1.) is there a source written or electronic which directs how much water flow different species of fish prefer.  <good question, but no authoritative work that I am aware of. Much of it is anecdotal or inferred by study of where the fish comes from on the reef... lagoonal and open water species preferring quiet flow, herbivores like tangs from reef crests and surging areas like stronger flow, etc> 2.) My PH is 8.3 middle of the day but my dKH id 10.4 and my calcium is 360.  <all quite fine... let the ALK fall a little if your like and you'll be able to bring that calcium up a little. Small matter though> How do I push my PH up without sending the alkalinity through the roof.  <ease up on buffer and use more Kalkwasser instead... that will raise pH and calcium levels> I am using ESV two part solution for buffer and calcium. <a fine product... my favorite brand of its kind> Thanks again for the help. James <with kind regards, Anthony>

Too much water circulation? Hi everyone! How was your weekend? <Too short!> A few days ago, the pump that I was using to return the water from the sump to the main tank failed. So in that hurry, I took one of the power heads from the main tank to replace the one who failed. Obviously the power head doesn't "pump" enough water so I went to buy another. The only pump I could find (suitable to be inside of my house without the night noise) was a "Little Giant" 5-msp (sump pump (submergible) which can propel 1000 gph @10' head. <Are you sure this is saltwater safe? My guess is no.> My tank is only 50 gallons, so that pump can drive 20 times the volume of my tank. It is too much? <No> I made a kind of flute with 4 nozzles pointed to different directions in order to create turbulence. Right now I only have 3 fish (2 damsel, 1 yellow tang) some hermit crabs, 4 turban snails, 1 brittle star, 40 pounds of LR, and a few polyps. My intention is to create a good place with good water flow and light to keep a reef tank. <Sounds like you are on the right track, but do double check that pump, though.> Thanks for your response, Carlos <You are welcome. -Steven Pro>

120 Gallon Tank Flow Rates Greetings to the WWM staff, I am setting up a 120 AGA that will be used as a reef tank and have just a few questions about the flow rates that the tank can handle. The tank measures 4 X 2 X 2 and has 2 overflows, one in each rear corner. The overflows appear to be drilled to accept a 1' drain and a ¾' return, respectively. <Fairly standard> I have a custom acrylic sump in the basement with a capacity of 90 gallons and will be pumping back up to the display. I will calculate the required head pressure and size the pump accordingly, but I lack some required data at this point and cannot arrive at a logical conclusion that is based on fact. I intend to fabricate some Durso standpipe devices so that the wife won't complain about noise and such coming from the overflows. <Good idea> I also would like to run (2) ¾' Sea Swirl return devices so that I have a very nice and turbulent water flow in my display. Since the tank will be dedicated to SPS, I think they will appreciate the water movement. <Agreed> How do I calculate to total capacity, expressed in GPH, of the 2 Durso standpipes? <I would look at Richard Durso's homepage. He may have the figures there. At the very least, information on how much water he runs through his overflows.> They will be 1' of course <Do double check your design. I believe Richard recommends using 1 1/4" or 1 1/2" PVC for the drain with a reducing fitting at the very end.> and I can size the pump accordingly but I certainly don't need a bunch of water on the floor in room where I will house my display. Many thanks in advance for your replies. Jason <Good luck to you. -Steven Pro>

Re: too much water circulation? Thank you for your response. I followed your advice, so I contacted the people from Little Giant, and they told me what you said "this pump is not intended to use in marine aquariums". So I return it and change it. Thanks. <You are welcome.> Just to give some practical things that I observed with my reduced flow. Maybe 2-3 days after the flow was reduced, the hair algae started to grow over some parts of the rock, then Cyanobacteria appeared in spots over the sand, the skimmer started to produce just green tea substance instead the coffee product. It is amazing how fast the environment can be corrupted when just one (and so important as the water movement) condition is out of the right performance. <Appropriate flow is a critical component.> Today at night my tank will receive the benefit of a new pump 850 gal/h @3' ahead (my tank 50 gal.) <Sounds good> Greetings <Have a nice day. -Steven Pro>

Water movement in clam tank Hello everyone at WWM, <Howdy> I am planning an 85 gal. flatback hex tank (48 x 18 x 24), and the critical species that will inhabit the tank are Tridacnid clams. Can you help clarify my confusion over the flow rate for the tank? <I'll try> Daniel Knop's book on giant clams states that "we have to do with much less performance when keeping clams. . . that is, five times the aquarium volume. . . seems reasonable to me." (pg. 147) That seems pretty low. <Mmm, it's okay... given "complete" movement of the water (little "dead areas")> I am trying to keep the specs of the tank as close to standard as possible to keep the costs down. The tank can be constructed with up to four 1" drains and four or six 3/4" returns connected to 3/4" centipede return fittings for directional control. With this setup, the flow rate should max out at 1200 GPH--yes? <Okay... bear in mind this is "real" flow rate versus an estimated value. In actual practice almost no pump installations yield near rated flow rates per interval> Now the $6,400 question(s): Is this flow rate appropriate for a clam tank? Too much? Too little? <About right. Most Tridacnid species, individuals will put up with, even enjoy greater water movement... as long as it's not directly blasting on them continuously> Any wisdom you can offer would be greatly appreciated. Your Web site has been a valuable resource for me in properly planning this tank. Thank you all! <Glad to hear this. Bob Fenner> Jeff

Circulation Situation Greetings <Scott F. tonight> Sorry to ask so many questions but I am therefore I ask. <I am here- therefore I answer!> I have a Supreme Mag drive 950 in my 55 gallon sump which is in the basement as my return to the main tank which is a 75 gallon it travels vertically 6 feet the return line that is. I have checked the flow from the overflow back to the sump as 690 gph. I used a 5 gallon bucket to test I got one gallon per just under five seconds. first question is . Is this sufficient? second I was thinking about building a somewhat closed loop around the tank with tees in all four corners with flexible ball joints to point flow where it is needed will the mag drive 950 still be ok or should I put a dedicated pump for my closed loop. <I like the idea of a dedicated pump for a closed loop. See Anthony's Book of Coral Propagation for some nice info. on circulation.> I of course would prefer to utilize the 950. By the way I am in the terrible diatom phase with my tank (brown patches on everything) rock, glass, powerheads. hope it doesn't last long :( <This, too, shall pass. Maintain good water quality, stay on top of changes, feed carefully, test...you'll be fine!> Thanks for everything, keep up the great service you provide to all us green horns. John S. <Thanks John, I learn more every day thanks to fine folks like you!>

Water Turnover Question Hello again!  <Hi there! Scott F. with you tonight> I've been reading through your pages and pages and pages of FAQs and I must say its very impressive, I especially like the stocking recommendations, fewer fish then most people want but I agree 100%! On to the point. My tank is a 125 Gallon, with about 20 gallons of sump I would guess. I am using a RIO 2500, hooked to a spray bar. How much do I want to turn over the tank for fish only? The return is coming through a spray bar I made myself, could this be limiting how much return the pump gives me as well? Do I need more flow??? How much should I be turning over a fish only tank? Most info I find is for reefs. <Not sure of the output of the Rio- but I like to shoot for 10 turns an hour, even for FOWLR> Also, I am planning to upgrade my SeaLife 75 skimmer to a AquaC 180. Is it easy to inject ozone into this AquaC skimmer? It has no venturi and no air stone, I want to be sure it will work before I spend the $350 on it! It was a huge headache and hassle making the ozone work with the SeaLife skimmer, I would rather avoid that in the future, I would of course buy the carbon outlet collection cup for the AquaC, just curious how you get the ozone INTO it! <Do contact Jason Kim at Aqua C. He is a great guy, and will be glad to talk you through the process. They have a great web site, too, which may provide some help> Also I asked about my Redox last time I wrote you guys, and you said let it be and let it do its thing. Its been 2 weeks now, and my Redox is now up to 148 (from 135), in the last 3 days it seems to be going up about 2-3 a day. Is this normal? Does it really take this long to raise?  <A rising Redox is always good. How slow or fast depends upon the conditions within the tank> I have also, since then removed all my sponges and filter pads from the tank, thinking they were leaching mass amounts of nitrates into the tank. The prefilter in the overflow box had never (in 2 years) been replaced, I just kept rinsing it. I really can't figure out why my water quality isn't that good. I just purchased a Nitrate test kit, so I will test when I get home, I suspect they will be high. <Good move removing the pads. Do test the nitrate regularly> Oh yah, Ammonia is .2 (I think because the tank sat empty for a week then I added a fish a week ago at least I hope that's why) Nitrite is 0, pH is 8.4, salinity is 1.024, and the temp. sits steady at about 81.7 (though it was down to 80.6 this morning so I just bought another heater, 1 200watt isn't enough for this tank). <Ammonia is a sign that something is amiss! And you probably should shoot for around 500 total watts of heaters> Attached are some pictures of the setup, any info you can give to help me provide a healthier living space for my poor puffer and future residence would be great. I plan to add 2 or 3 more fish to the porcupine puffer, some type of large angel (juvenile though), maybe a wrasse, and something else nice but not to huge. Below is a list of what the pictures are of. Which reminds me! Last thing :) I've had the puffer for 2 weeks almost, and he never comes out when the lights are on. All day and evening when the tank lights are on, he sits under a rock and hardly moves (sleeping), then as soon as the lights go off, out he comes...even at night he's not real active, he pretty much just paces up an down in the corner of the tank, but he does eat (krill with Kent garlic Xtreme added to it) at night when he is out! Any idea what's up with this? He twitches and spins sometimes too, but not a lot. <Well, the ammonia reading might have something to do with it...> 125gal_salt = tank as a whole Overflow = Overflow box in the tank, not sure on its GPH, its an older AMiracle overflow. Spraybar_return = my spray bar with a RIO 2500 on the other end, I believe its 1/2" PVC with small holes drilled in it, not 100% sure on size of the PVC though. Sump1 = my main sump w/ bioballs and heater in it. Later added a 2nd sump to hold more water and spread things out (AquaC will go here later I think) Sump2 = My addition sump, and Ozonator (useless pic other then shows the skimmers to small) Collection Cup = My homemade collection cup, holds carbon to filter ozone from the air (1 hour at home depot and $5) Sump2_Inside = Useful picture, shows my skimmer, RIO 2500 return (has an elbow on the end for when the water level gets low), Also homemade carbon filter for ozone skimmer water return, and a sponge that does nothing, its only 1/4 under water, I may just take it out tonight it may be a nitrate bed?? <probably, if not cleaned> Sump1_Inside = Heater, a Minijet powerhead just moving water so it doesn't stagnate on the surface like it was, my ORP Redox meter hangs over the overflow drain tube. Overflow2 and Overflow3 = My older style AMiracle overflow box from the outside, with sponge removed. Any idea how many GPH this does? Will I need a new one if I upgrade to a bigger return pump? or a second one? <Check with the manufacturer to see how much flow it can handle, and modify as needed> Thanks in advance for your help! You guys are great!! <And have fun! Good Luck!> Mark

Circulation Hi, again. I have a 75 gallon reef tank, with a Yellow Tang and a few other fish. For circulation I have 2 Rio 2100's (I know, but I've had them for a while) <I know they have a bad rap, but I also know of quite a few people that have them and have never had a problem. I would not recommend someone go out and buy them, but I would not tell you to throw them away either.> on one side, at the top and bottom of the tank and shooting sideways, and a Rio 2100 on the other, also shooting sideways. In the middle, at the top and back of the tank, I have a 300 gph powerhead shooting out towards the front. <Ballpark of a little under 2400 gph total.> Flow seems good for the corals (they seem happy), but the fish seem to swim upstream quite a bit. I don't think they're struggling, but I'm wondering if I should lower the flow, or change it somehow. <I would leave it alone. I don't think it is anywhere as powerful as the ocean.> I don't want to have to replace the pumps I already have if I don't have to, and I don't know if I should lower the flow, since the corals seem quite satisfied. Is it too much, or do I just need to distribute it better, or...? Thanks for the incredible help you provide reef enthusiasts. :) Arthur <You are welcome. -Steven Pro>

Re: Flow/Circulation Recap - 75 gallon tall reef tank, 2 Rio 2100's pushing water from one side, 1 Rio 2100 pushing from the other, 300 gph powerhead pushing from middle back of tank forward. Corals like it, but the fish seem perturbed. I didn't think that I have too much flow (and based on your response to my last e-mail, neither do you), <Correct> but the fish (a powder blue tang and a clown fish) spend much of the day "leaning" into the current, looking like they're swimming upstream. They seem to seek out the pockets of the tank where current is strong. <If they seek out these places, why would you think they do not like it? There are obviously some low flow areas they could escape to if they wished.> The clownfish especially looks overwhelmed, I guess because he's so small. They look uncomfortable. Is this an issue, or can I relax and let them be? Arthur <Please relax. This is nothing for them. -Steven Pro>

Circulation, aeration, tank top, cc stars... >Thank you so much, but how do I size the additional powerheads? ><A couple of hundred GPH will be fine. Do arrange for the intakes to have a "pin-ball" piece of wet-dry media in their intakes to prevent animals being sucked in... and place these pumps in a fashion, where >they can be easily removed for service, cleaning. Bob Fenner> Okay, Bob, more questions. I ordered 2 powerheads that arrived tonight and I finally sat down and read your book and Michael Paletta's book. Loved them both, and I finally feel more capable of asking some more "right" questions. <Hmm, okay> 1. I got a Hagen 201 and a Powersweep 214. Aren't the strainers that are installed on them enough to keep critters out? I can't for the life of me even figure out where I would insert a bioball into these, since the strainers both protrude. <Yes, these are good powerheads... that come with their own sufficient strainers... the above note is to emphasize the importance of having same... not to remove, leave off...> 2. I have always been concerned with the aeration of my water. Will the Caulerpa in my refugium/sump be adding enough O2 back in to mitigate my concerns?  <It will indeed help... especially if constantly illuminated, or alternatively the sump is lit during "lights off" on your main/display tank> I redirected my sump return about a year ago so that thetank surface is getting a little rippled from it. Is that all enough, or should I utilize the venturi air intake on the Hagen powerhead? Would the resulting bubbles be a problem for my current or future petfish and invertebrates? <You can test for dissolved oxygen with kits, meters... but would just observe livestock here... all likely fine> 3. When I upgraded my lighting to a SmartLite, I removed my tank top and the lens on the light to allow the greatest light transmittance. This leaves some large gaps between the light and the tank rim where things might escape. After reading your book, I am concerned that might happen to me in the future. I am also worried about water splashing on the bulbs. I don't have a hood and the SmartLite canopy (do I havethose backwards?) is resting on the center tank support. It has beenthis way for about a year and everything has gone well (except for increased evaporation loss). Should I stop this foolhardiness and put the top back on my tank? I don't have any corals yet. <I would leave all as is... and not worry> 4. I have a very large and a very puny chocolate chip starfish. They used to be the same size and one shrank and the other grew exponentially. This monster is now about 5 inches wide. I only have some damsels now as far as fish are concerned, but I am trying to plan my future stocking plan. I'm pretty sure I will have to remove the damsels because they have been allowed to rule the roost for too long and are very large and probably pretty aggressive. Will the starfish have to go back to the store too? My children and their friends love the starfish. <I would leave them be as well.> 5. I successfully battled off a terrible turf algae invasion a couple of years ago, mostly by introducing a small cleanup crew to the tank. The live rock is not very interesting now, except for a couple of fan worms and some other wormy looking stuff and I do have coralline algae, although it does not cover the rock yet. I am going to get more on top of things like calcium. I don't supplement and so the tank is only replenished by small frequent water changes. Should I add some new pieces of live rock for interest sake or leave well enough alone? I guess the starfish is probably eating a lot off of the rock too... <Would likely add a bit more live rock... new livestock you plan on will change many dynamics, reveal other life going forward.> I am getting more responsible and conscientious every day. Even if my tank takes forever to get to where I want it, my next trip to the local Monterey Bay Aquarium will be great now that I feel more informed. <Ahh, the pleasure my friend> Thanks so much. Linda Swenberg <Be chatting, sharing. Bob Fenner>

Return pump and powerheads Hello again! I have finally started to acquire the equipment to set up a FOWLR aquarium where I also want to add some soft corals and polyps over time. I thank you for your previous help and I have a few more questions. I now have a 75gal reef-ready tank with an Oceanic PowerCompact light (110W, w. Coralife white and actinic blue bulbs). I intend to put a 20 gal sump underneath it, probably an Oceanic Sump model 1 (it will be difficult to put something bigger because of the doors/supports of the cabinet: Oceanic cherry oak cabinet). I realize I may need more light for the corals but that will have to wait for now. I do intend to buy around 90 lbs of live rock after I get the skimmer and sump. Here are my questions: 1.) I will get an AquaC EV120 filter with a Mag-Drive 5 pump. I could get a Dolphin DP-560 pump for the same price. Do you favor one over the other? I have only seen the Mag Drive pumps locally. <Both are fine.> 2.) My second inquiry has to do with the return pump. I believe I need about 750 gph through the sump plus some additional powerheads in the tank to turn the water over as much as possible. At the same time I want to balance the water flow to the sump to not make the system too noisy. I am planning to set up a Durso style standpipe (see http://www.rl180reef.com/pages/standpipe/standpipe_frame.htm for a description or http://home.att.net/~rstockman/overflow.htm for a more compact modification) that my LFS says really reduces the gurgling noise from the water falling down into the RR overflow box (if you know of other good methods, please let me know). <This one is about ideal> However, I have heard that if you get too big a return pump, noise will still be a problem. Is a Mag-Drive 9.5 too much? <Yes... by about twice the flow-rate... Depending on what you want to achieve in this sump arrangement (definitely not a refugium at this turnover rate), a good five, six volumes of the main system per hour is fine> The pump will be in the sump under the tank and will have to push an almost 5 ft. water column. I saw a chart at marinedepot.com that says the Mag-Drive 9.5 will push 750 gph with a 5 ft column. Others have recommended to just use a Mag-Drive 5 or 7 (250 or 420 gph at 5 ft). What would you recommend? <!, the same> Less flow through the sump but more in powerheads? More flow through the sump? <The former> 3.) I am planning to use a few powerheads in the tank. Maxi Jets seem fairly inexpensive at marinedepot.com. Is it better to put in say 4 MaxiJet 400 @ 106 gph ea, or 2 (or even 4) MaxiJet 1200 @ 295 gph ea?  <Four smaller> I am concerned about too much flow from a single nozzle. Is this a problem? <Yes, can be... animals, non-life getting sucked-up, blown about> I don't have a good gut feeling yet for what these flow rates mean in terms of turbulence in the tank. <You will> Thanks for your help. I trust your judgment more than most of my LFSs. <Trust only your own ultimately. We are all humans. Bob Fenner>

Lots of Questions - Jason breaks down A) I have a MTC Pro 6500S Skimmer - it is about 2 feet high. It is powered by a Rena 400. Is this powerful enough. <<I should hope so. Two feet is quite the reaction chamber.>> Is there some sort of conversion chart to figure this stuff out, or do we just have to ask the experts - like you. <<no conversion chart too many variables, mostly as all skimmers are not created equal.>> I am a little confused on this - do people use powerheads to power their Skimmers??? <<some people do - certainly one of my three skimmers has a powerhead running it.>> Can you recommend 1 for me??? <<that skimmer is running with a Rio 800. Some people like maxi-jets. You could ask this question on the WetWebDiscussion Forum where you could get easily 10 opinions on this: http://talk.wetwebfotos.com/ >> B) When I read that you should have 10x (is this correct for an avg reef tank) the turn over of your tank size per hour. <<It's a good number to shoot for, yes but not worth killing yourself to accomplish>> 1) Do they mean 72 gallons - 20 gallons LR - LS = 50 gallons??? <<no, it means 72g + ?g in the sump = X total system gallons.>> 2) Do you count your return pump from sump 600 gph plus the power heads you have in the tank itself 3x200 gph??? <<depends on who you ask. I would cast my vote behind total flow - powerheads + circulation pumps.>> (I would have 1200 total.) <<are you sure you're getting 600gph at the head in the tank. Many pumps that have a rated output of X drop to X minus something as you raise the output away from the pump [head feet]. You may only be getting 400gph. But in any case - what does it look like in the tank?>> C) I am having problems with gravity flow from my overflow box. What causes the bubbles to be created when it is released from the tube into the water. The tube is about 1 in underwater and the tube is a 25/34 mm Eheim - I think from what I have read the hole is 1in on the overflow. - I have read that the overflow can't handle the GPH from the pump. Mine is Rio 2500 it pumps the water 4 ft to top of tank. <<ahh yes, Rio 2500 pumps approximately 520 gph at 4' according to Rio.>> The tubes are the wrong size, or that there is a vortex that is created in all of these overflows. <<Much talk of an overflow that you didn't name - who makes the overflow?>> I have take of the pre filter pad on the skimmer to try increase flow rate, Put a small tube down the line to increase flow rate and stop the vortex, I have added some foam pads, I have prayed. These don't seem to make a big difference. <<you've confused me - we're talking about skimmers now? In any case, not sure any of those things would have helped if things were designed to work to a certain limit that you are now exceeding (?) - very hard to tell. Perhaps some more detail on these pieces/parts.>> The only thing that has worked is to lower the power output from the Rio - but I think that works b/c less flow equals less bubbles created b/c less water is flowing through the tubes. The neg is less filtration :( <<are you strictly concerned about the gurgling noise from the overflow? If this is the case, do try to get used to it and let you tank enjoy the increased flow.>> I have checked your site thoroughly and have not found any definite answer on these - sorry If I am asking questions you have already answered. What can I do stop this problem I don't want to 'kill' the bubbles after they are created I just don't want them created at all. <<in the overflow process? almost impossible to avoid some, is mostly attributed to the design of the overflow, which... you didn't tell me who makes it so I'm really not sure which direction to point you in.>> Thanks for making life a little easier for all of us :) Brad <<Well thank you. Cheers, J -- >>

Follow-up on Lots of Questions - Jason tries again Thanks for the reply JC <<No problem...>> -A is regarding a skimmer. I wanted to know if the Rena makes enough bubbles for the skimmer. <<I think so, yes.>> Please tell me what aerator you recommend besides Rena and what strength it should be approx. <<Check with the manufacturer for your skimmer.>> Can it be too strong??? - What would happen with too many bubbles in the skimmer??? <<Don't think it could be too strong.>> -B is regarding powerheads - ah... <<did I answer that one well enough for you?>> -C is regarding Overflow. The overflow is the one that comes with the All-Glass Tank 72 bow front- I assume it is a All-glass. <<Ahh ok, the built-in overflow - I have one of these myself in my 75. >> 2 tubes in over flow - 1 return and 1 intake. The intake is about 16 inches tall - There is a solid white pipe that is 12in long then continuing a clear pipe with square holes all around it for the next 4in. <<yes - very familiar>> The water level is about a 1/2in above the white pipe. <<<are you strictly concerned about the gurgling noise from the overflow>>> I could care less about this. <<ok>> I just want to get rid of the bubbles and use the overflow to its max. <<what bubbles? I'm not sure I understand where those are coming from...>> I have told you the make of the overflow in hopes you can help me further and answer the questions you were unable to b/c you did not know the make <<right, well now you know I have the same overflow so I can probably answer quite a few questions about it.>> D - New question Do you know of a powerhead that has a foot print of 4in x 5in that is as powerful as the Rio 2500. That is all the space I have in my sump and I don't have the means/know-how to cut acrylic. <<Can't think of one... you should browse the web and some online fish stores and see what you can find.>> Thanks again. Brad <<You are welcome. Cheers, J -- >>

Water turns A brief question regarding water turnover in a 15-gallon young (7 weeks old) reef aquarium. I have a CPR skimmer (Rio 600 pump) and a Via Aqua pump. Between the two I figure I'm getting about 280 gallons/hour total flow. I added a P. Ocellaris to this (main tank) yesterday. Last night when I noticed he looked stressed and was hiding in the corner. I turned both pumps off and this morning he looks better. Are these pumps providing too much by way of water turnover in my tank? Would I be better off removing the Via Aqua-- or alternating between the two? Thanks, Greg <This is a bunch of water movement for such a small system, but the Clownfish's behavior likely has little to do with it. Water movement, "changes" in the wild are often many times this factor. The hiding, hanging in a corner or bottom is mainly due to being moved, placed in new circumstances. You could practice alternating the pumps to see if this suits. Bob Fenner>

Question (Rate per what function?) I just bought a 150 gallon tank and I want a fish only saltwater aquarium I just don't know how many gallons per hour I need for this to work. Please email me back. Thanks for your time. Chris <What? GPH for? Please read here re marine water circulation: http://www.wetwebmedia.com/circmarfaqs.htm and the linked files beyond. Bob Fenner>

Water flow Hi Bob & everyone: <cheers> I have 2 questions about my 60 gallon reef tank. The first one is about water flow. I have a Fluval pump filter circulation of 225 gallons per hour. The Fluval is theoretically for a 100 gallon tank. I have one of those "bubbler" things that I plug in that looks like a waterfall. <still not enough water flow for this tank by itself... 4 to 10X tank volume per hour please> I have about 2and 1/2" inches substrate - broken coral, shells, etc. and it really gets dirty under there. <because it is too course. Weekly siphoning is needed with this type of media> I also have a CPR backpack which is very effective for 6 fish, crabs, live rock, etc., but I feel that the substrate should get more aerated.  <agreed> I stir it up every couple of days and worry that the dust that comes out of it will make my fish sick, if not now, later. <not to worry about> Should I make the switch to aragonite or could a use a powerhead or two to get water circulating through the substrate?  <you need MUCH more water flow here please> If I put a powerhead in there, how powerful should it be.  <two pumps 300gph or bigger would be very nice for this marine tank> I just bought one which circulates 40 gallons per hour and that just doesn't seem to be nearly enough .  <agreed> It is a Rio 50. I should add that my fish are small, so I don't want to blow them out of the tank, either. <pump size does not do this... improper direction does. Place the 2 PH in opposition so they converge for random turbulent flow rather than sever linear/laminar flow> I am down to 2 mithrax crabs now and am happy to know, thanks to you all, that they don't start eating fish until their bodies are 2" across. As ever, thanks for all your help!! Connie Cavan <best regards, Anthony>

Bulkhead Drilling Hello Steven, Recently I bought a used 100 gallon acrylic tank and my intention is to make it FOWLR. Right now it has one corner over flow with a 1 inch bulkhead at the bottom of the tank. From what I've been reading (FAQ's from www.wetwebmedia.com), your suggestion was to increase water turning rate meaning drilling more bulkheads. <Correct> Would you please let me know what's the good turning rate for my tank and how many more bulkheads should I drill to accomplish that rate. <This depends on what in particular you wish to keep, but somewhere in the neighborhood of 10-20 times the tank volume per hour. I would use at least three 1" bulkheads in a 100.> Also the suggest location of bulkheads (important). BTW, I'm using plenum so I prefer not to drill at bottom. <I drill most of my holes near the top. You can see a very nice diagram excerpted out of Anthony Calfo's "Book of Coral Propagation" here http://www.wetwebmedia.com/plumbingmarart.htm> As always, thank you very much for your help and advise. Regards, Dung Ngo <You are welcome. -Steven Pro>

Re: Flow in a reef tank Hi, I'm assuming the best way to do this would be to split the return with an adapter from the pump to opposite ends of the tank? <or with a manifold that has 4-6 nozzles (adjustable or on a complete loop to even volume per nozzle)> Does it make a difference if I split return close to the return pump or wait longer?  <I'd wait for the tee or manifold tee at the top of the display> And if I am using 3/4 inch return tubing for one line, should they both be split at 3/4 or two at 1/2 inch each?  <requires some experimentation... all dependant on pump volume at head> Thanks for all your help thus far--it has been great! Keep up the great job! Mike <thanks kindly, Anthony>

Flow in a reef tank Hi Again, Should the current in a reef tank (75 gallon) be clockwise or counter-clockwise? Does it make a difference? Thanks, Mike <neither are favorable... random turbulent flow or surge flow is best. Have opposing outlets converge upon each other for a nice random dynamic pattern (as in back left and back right discharge aimed to opposing front left and front left corners). For a 75 gallon reef tank you will need a minimum of 800 gph water flow... likely though that will not be enough for most species. Aim for 200o-3000gph for most tanks (more for sps corals and gorgonians). Best regards, Anthony>

Circulation Is a 1200 gph external pump excessive for a 75 g tank with 50 lbs of live rock? I wanted to point two pvc outputs at each end of the tank towards each other to create ocean-like turbulence ( I am thinking of the last time I swam in the ocean myself. My setup now is with Rios 200 x 3 and this must be puny compared to a real reef). Also, I don't want the intrusion and heat from more powerful Rios. I have experienced a few coral deaths in the past from rapid infections (I assume they are bacteria because the previously healthy specimens disintegrate and dissolve within 24-36 hours). Any suggestions for a good pump. Thanks in advance. >> Rarely is circulation "too much"... and I agree with your philosophy... from direct experience. At 1200 gph you could have a good submersible (my fave choice is an Eheim), or a good external magnetic drive (am still a big fan of the Little Giant MD-SC series here... Iwakis produce too much heat...) Bob Fenner

Re: Filter Flow Rate Rules of Thumb... Bob, thank you for your opinion on the number of fish I already have in my tank. I have taken heed!!! Therefore, I shall resist any more until the proper time. <Ahh, this is best> You also advised me on the type of canister filter that was a good one. Actually, I had been looking at the Eheim filter Model 2026 (which can be seen at www.petwarehouse.com), and this filter claims to have a flow rate of 250 gph. My question: is there a rule of thumb which, based on the size of your aquarium, would dictate the minimum flow rate of a filter??  <Hmm, "the more the merrier"... a few times the tank volume per hour (3,4-10 depending on the types of livestock, arrangement of plumbing...> Do you think that this particular filter would be suitable for my reef tank?? <Yes, a very fine product> Also, I have been watching for your books at the bookstore. Has the newest one been released yet?? <The Fishwatcher's Guide... is available through a few places... including through our site: www.WetWebMedia.com... check under/over the links to "Books for Sale".> Thank you for your valued time & knowledge!!! Pat Marren <Glad to be help. Bob Fenner>

Circulation  Hey Bob, I just started cycling my tank three days ago (60 gallon tank, 80lbs. live sand, 90 lbs. live rock - pre-cured). Two questions: 1.) My tank absolutely reeks! I think it must be the rise in ammonia, though the smell makes me think something else might be amiss. Do I need to do a big water change?  <Very likely yes... I would... do you have test kits... for pH, alkalinity, calcium levels? Do change the water in any case... and add some activated carbon in your filter flow path> Will this go away by itself anytime soon?  <Not soon enough...> 2.) I'm confused about how much aeration I need in the tank -- I have decent circulation (app. 550 gallons per hour circulated). Does the water surface need to be agitated? <Yes... a dissolved oxygen test... or Redox would aid you here> Should I have the powerheads release air bubbles as well? <Not necessarily... but the surface should be disrupted.> Aesthetically, I wouldn't prefer it. A necessity, though? <Well put... Please read through the "Circulation" section of the Marine Index on the www.WetWebMedia.com site for more here. Bob Fenner> Many thanks! Javier

Pump question Hi Bob (or Lorenzo),<Bob currently> Here I am almost ready to put my whole system together, then put live rock in and get it going. Here is the set up: 55gal tank ---> overflow box ---> 3ft. tall 4.5in diameter protein skimmer (in sump - 35gal total, but only about 20gals of water in the sump) ---> through baffles ----> refugium ----> more baffles ----> pump? ----> back into 55gal tank. My question is,....how do I know what size pump to get? Doesn't it have to equal (or close to equal) the amount of gallons per hour the overflow box is sucking out of the tank? If so, then how do I measure this amount? with a gallon jug and a stop watch? <A possibility. Please see the "Pumps, pumping" section on the Pond Index part of the www.WetWebMedia.com site here> Please help me help my tank not to spit up all over my floor. Thanks, Jana p.s. Good idea: I was thinking,.... since we aquarist are forbidden to use soap or soap like products on our equipment, wouldn't baking soda be a good thing to use to scrub out hard stains? <Yes, as long as you're careful not to scratch soft materials> My mom always taught me to use baking soda on hard to remove 'gunk' on dishes and pans, and Bob Fenner always taught me to add a few teaspoons of baking soda a week on my tank to keep pH levels above 8.0. So wouldn't using baking soda to clean your equipment be a good idea, considering most of the baking soda is washed off with warm water after scrubbing? <Yes> Just an idea, please pass it on to others if you like it would be alright to do this. Later, Jana <Be chatting my friend. Bob Fenner>

Re: pump question Bob, Do you mean my system needs to turn over 10 times my tanks volume per HOUR? <Yes... about this rate> Whew! That's' a lot! Also with a 55 gal main tank and a 35 gal sump with about 20 gals of water actually in it, this is a total of 75 gals?  <Actually, the calculated rate is ten times the system volume. That is, about 550 gph> (I do include my sump tank amount when figuring out total volume, Hu?) I read over the articles on the pond section. I feel like my brain is frying. <We ought to start a club> I thought I was almost finished. Wrong! I am off to search some more for more clarity. Jana <Ah, tis pleasurable. The water movement in most parts of the seas is much greater... by far. Bob Fenner>

Re: Pump and refugium and circulation in general question Thanks, a few more quickie questions though, (still about refugiums). When I explained to you that my refugium set up will have more then 1 sump, you said the other one could be used for live rock, and sand bed. You also mentioned this to someone named Rick in the FAQs who is setting up a 807 gallon reef tank( I could only DREAM of something like that!!). Is this because you're assuming the refugium will be housing some type of fish, or such, because mine will only be for macroalgae, and I assumed the LR, sandbed, crabs, and snails etc...., and the second strictly for total volume, or is there a reason I should put the LR, and such in the other sump away from the macroalgae.  <The difference (in location, use of pumps) is almost certainly for limiting the flow rate through the refugium itself. Two, three or so actual volumes per hour is generally ideal for such sumps... and most folks "recirculation" is more than this... often much more> If so, then what exactly goes together in which sump, and why, because I did not see any mention of separating these from one another. The only thing I saw which could relate is the mention of plenums, or barriers, which I thought was just to break up the flow a bit? <Mmm, much to say here... the plenums serve several possible/real functions... the barriers as well... but not the same... Don't get me wrong, but you would do well to "read books"... not try to gain complete answers in these sorts of formats of learning...> Also will everything not eventually get mixed together by the current going through the bulkheads? <Hmm, yes, no... Bypass water from some parts of the same system will eventually be mixed... but not quickly if the "refugium" circulation is more limited... Bob Fenner> Greg N Montreal, Canada. P.S. Can I use crushed coral in the refugium, ( I have lots left over from my tank setup) or does it have to be sand, or is the layering of the two with screens between better in this case? <Crushed coral is fine.>

"Hey bob" (Water movement) I have a quick question for you. I have a 40gallon reef tank, the inhabitants are 1, 4inch blue super crocea clam, 1-green-tipped frogspawn, and various xenia colonies. Here's the big question: I have a aqua-clear 402 powerhead on the left side of the tank giving current toward the opposite side of the tank, and I also have a little Rio powerhead 800,on the opposite side of the tank going towards the other powerhead current. My question: is this too much circulation for a 40, gallon reef tank? does it bother my corals? please help.  <What you list shouldn't be too much water movement... but the only way to tell is by observing your livestock. Does your Xeniid colonies and frogspawn coral open up? You're likely fine here. Bob Fenner>

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