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More FAQs about Plumbing Closed-Loop Return Manifolds 2

Closed Loop Manifold - 12/11/2005 Hello guys from WWM! <Hi there Pedro! You've got Josh again.> Do you think it will make a lot of difference in flow if I make the return line for a 75g which is 3/4" to 1" to the top or beginning of the loop, then tee off for 3/4" pipe for the loop and outputs or just don't even bother of drilling the hole bigger for a 1" bulkhead and just do the 3/4" pipe all around. Does the CLM need to be separate from the filtration cycle? <Nope. Just make it the return from your sump.> I don't have anything setup yet, I'm in the planning mode. I don't have a pump for this right now, but will like to have a descent flow. Any recommendation will be appreciated. Need advice ( size and Brand )on an external pump that can be use as a return pump for main display and another for the Closed Loop Manifold. <You're fine with the Mag Drives, and the good news is you only need/want one pump to return water to the tank via your closed loop. Running two will be a problem as no two pumps will ever match each other precisely (you'd basically have to set up a sump per pump). Just size up to perhaps the MD12 or MD18 and control the output with a ball valve and more outlets.> I have a Mag 7, which the LFS sold me, but now I understand that's not enough. <If you're not running it yet, why not return it toward a bigger pump?> What can I use that mag 7 for? Is it too much to use on a skimmer? <Depends on the skimmer really. Find one that operates best with at least 700 gph and I don't see why not. Personally, I always have some crazy scheme for spare pumps. Cheapest route would be to try and take it back for a credit.> Thank you WWM. Pedro Velasquez. <Sure thing Padre...uh Pedro> Manifold Recirculation Loop Made of Funny Pipe? - 12/06/2005 Hello crew ! <Hi there Pedro!> I have two questions: First one is fairly simple. I would like to know if the Manifold Loop can be made out of Funny Pipe or sprinkler plumbing. <I'm not familiar with Funny Pipe, but if it's of the same nature as sprinkler plumbing then I would be concerned about possible algaecides.> The second one more complicated: I have a Mag 7 as my return line pump for a 75 gallon reef tank ( not set up yet) and about 4 ft of head and the return line is a 3/4". I will keep the overflow the same 1". Do you think if I make the Manifold Loop to 1/2" reducing the return line, will give me the necessary flow? <No. Making the loop 1/2" will restrict the amount that the pump can push into the loop, thus restricting flow before it even hits the outlets. Instead keep the 3/4", reduce the amount of outlets and use the outlets themselves as the reducing point (lock-lines are great for this). That said, the Mag 7 (@ 700 gph.) is on the short end of desired flow. To get at least 200 gph. from your outlets, you could only have about 3.> Or do I need a bigger return pump. <Would be better.> I will keep the overflow the same 1". IF you please can point me in the right direction it would be very well appreciated. <Since you're not set up yet, why not add a second drain to help accommodate more flow? Remember to plan for future intentions and not just the quickest way to get up and running (hard to, I know). A larger pump will serve you better, but don't over shoot your drain capacity.> Thank You, Pedro Velasquez <Anytime. - Josh>

Re: Closed Loop Manifold! - 12/13/2005 Thanks Josh, for the quick reply! <No problem. My wife had some things to look up, so I took the rest of the night off.> I got the CLM a bit more under control now thanks to you. <Glad to help, but I'll pass all credit to Mr. Calfo.> I just don't have very clear about the pumps having the MD 7 & MD 9 pumps running together. Wouldn't this be more complicated, and I guess they have to be connected in parallel right? <Much more complicated. Remember, in my first response I said you would only need one pump. If going with two, they would have to be separated entirely "a sump per pump", not parallel.> To make things easier and simple, I think I will buy a bigger pump, like you said. <Good choice;)> But I just found out that the MD pumps are not recommended for saltwater external use, is this somewhat true? <Not really. You just have to look for this specific ability in the pump listed. Look at the Mag Drives here http://www.drsfostersmith.com/Product/NavResults.cfm?ref=3532&subref=AG&N=2004+113041 .> Because I would like to go external to lessen the heat. How about Sequence pumps? Gen-X, Iwaki, Blue line or any other that's reliable and cost saving on electricity. <All would work as well. I didn't mean to get on a Mag Drive kick, that's just what you already had.> I could then use the MD 7 for the skimmer. Is this a good idea or is this pump to much for a skimmer? <Again, depends on skimmer specs. Would be a big one though.> And to have this clear : Is this pump or pumps that we are talking about just for the filtration cycle or is this for the CLM? I want to have them separate with the CLM on a timer or wave controller. <I think you've missed one part. If done properly, the CLM will create all the random, turbulent flow you need. No need for the wave controller (saves money on electricity also). If you're worried about feeding time, just adjust the output with the ball valve. So, I mean one pump total. Return from sump is the CLM.> The filtration cycle is the standard corner overflow of 75 g: 1" Overflow; 3/4" return but with an addition of a "T" 2 outputs instead of just one. The CLM is 3/4" all the way with 6 "Ts" and 1/2" outputs like you advised me to do with loc-line nozzles and the input for the loop is 1" I think I need to buy 2 pumps, one for the filtration cycle and one for the CLM. Please tell me what you think. And thanks again man.. <No sweat Pedro, the filtration question you have throws me though. The sump is "powered" via gravity so I don't understand where you feel the second pump is going to help. If I'm missing something in your meaning just shoot me another message. Hope I've cleared up the rest. - Josh>

Re: Closed Loop Manifold - 12/12/2005 Already took care of the return pipe issue. I'm going to leave it 3/4" and not mess with drilling. This is the main return from the sump to the tank. I want to keep it separate from the Loop. What pump would you recommend! <Did you not receive my e-mail last night? As stated, I would go with the MD12 or MD18, add the extra outlets and limit output to desired flow with a ball valve. If running the MD7 as well, just get the MD9> I had the Mag 7 for this return, but I think is too small. <Correct, won't give adequate flow.> About the CLM: I'm not sure about the output size on the loop. The loop is 3/4" inside of the tank. Should I have the "T's" with a reduction to 1/2" or should I leave it 3/4"? <Reduce to 1/2. Find a way to taper this down as well (lock-lines or similar object).> It's going to have 6 outputs. 4 now, 2 later. <Why not six now?> I have no way of knowing at this moment how the flow is going to be, because I don't have the pump yet. I would like advice on a pump for the CLM with 4 T's & 2 90 elbows and 2 three ways on two corners for a 75 gallon tank. I would have about 2 1/2 feet of head. <Try rereading Anthony's article on a closed loop manifold. I feel that aside from its effectiveness, the beauty is in the simplicity. - Josh>

Closed loop system question 11/24/05 After reading pages of your FAQ's and related posts on a closed loop system, I'm convinced! Will attempt one for my 65 gal w/25 gal fuge. I'll use a Mag 9.5, head is about 5', return pipe 1" from sump section of fuge. Question: Wouldn't a 3-sided rather than closed loop work? <As in... three discharges instead of more? Okay> More water flow, all aimed toward center of tank? <Better for this to be more complexed, multidirectional> Also,--if system is just below water level, even if jets are aimed a bit lower, wouldn't the movement of water near the bottom of a 24" deep tank be rather sluggish? <Yes... better to aim some discharges toward the bottom...> How is this negated? <Nozzles, elbows...> Could I run some PVC down lower, vertically, off the main manifold at the top? <Yes... though do bear in mind the possibility of water siphoning out... should there be a break in the lines behind/below the tank> This forum has been inspirational, to say the least. Thanks..... Barry <Thank you. Bob Fenner>

Closed Loop Manifold 11/18/05 Hi crew, how's it going? <Pretty good> First off, thanks for all of the valuable information you guys provide. It's truly mind-boggling how much knowledge you all have. As most people who post questions to your site, I have read through a great deal FAQ's questions before deciding to post. Also, after reading through Anthony Calfo's article, I became interested in setting up a return manifold in the future. I'm sure my questions will be very similar to others who have posted, but I want to be on the safe side before I even get started. I sort of have an idea of how I want to approach creating the closed loop manifold system. First of all, I'm interested in setting up a 125 gallon reef tank with soft and stony corals. The dimensions would be 72" Long X 18" Wide X 20" Deep. I plan to use a 60 gallon aquarium that I have laying around as the sump (It'll only be enough water to fill the main display and maybe half of the sump). I want to use a CPR CS150 hang on overflow box, which has a flow rate of 1600 gph (the only reason I'm considering using this overflow is because I currently have a CPR CS50 overflow for my 40 gallon reef tank. It's been up an running for about 2 years and I have not had any problems. Not even close. <Mmm, okay... but one (semi-final) suggestion to have the new tank drilled instead!> I consider it very reliable). For the manifold, I want to have it connected to the return pump from the sump. The pump I'm thinking about using is the submersible Mag-drive 36 which runs 3600 gph at 0' (I've also had good success with using a submersible pump for my return with my 40 gallon. I also like how quiet submersible pumps are). <Yes... though issues of waste heat, potential for electrical difficulties still make me a bigger fan of immersed> So I did some calculations for the manifold based on what I've read on the FAQ's. Assuming that I will have a maximum height of 5' of vertical plumbing, the slow rate of the Mag becomes 3050 gph. Then I added the following addition feet for head lost: 5' loss for (5) 90 degree elbow bends, 1.5' loss for 15' of total horizontal plumbing, and another 1' loss for the combined nozzles. So now I'm at a total of 12.5' of head loss, which for the Mag 36 comes to 1850 gph. <About right> So now I've divided this 1850 gph by the 300 gph that you guys recommend for each nozzle at 1/2". This gives me the (6) nozzles. I was thinking of having 3/4" PVC for the entire return line and the (6) 1/2" nozzles (adjustable of course). I want to have the nozzles located similar to the attached picture, looking from the top. <Okay> In addition, I plan to use my current Rio Pump (750 gph) to circulate water behind the Live Rock, halfway down the tank at the back wall. Of course there will be a hole drilled at the top of this line in case of pump failure. Based on all of this information, do you guys feel that I would have adequate circulation for a 125 gallon reef tank with this set up? <Mmm, yes> I appreciate any knowledge you can shed on this situation. My apologies for such a long post. And thanks again for this service. Cue J <Thank you for writing, sharing. Bob Fenner>

Closed loop design input sought 10/28/05 Hi All, <Chris> Could you just give my plan for a closed loop style manifold for my sump return the once over with comments and suggestions in your usual fine style. <Could> Tunze recirculation pump from sump (Master Recirculation Pump (1073.030) , this has a 1" (25mm) output so I was planning a 1" pipe (hard) from this to a bulkhead in the base of the tank (inside weir area) sized for the 1" to pass through. At water level in the main tank the feed pipe will be split to run around the tank and T'd down to Â¾" at this point, the manifold will run in a loop all around the inside top of the tank. I was thinking of fitting reducing Tee's to the outlets to reduce outlets to Â½" with Â½" 45deg's added for flow adjustment. <Likely the best route to go> The specs for the pump indicate about 500 GPH (2000lph) at a 1.5 meter head (static head will be less but I have allowed a little for bends etc) which is the 10x turnover I am aiming for the Ecosystem sump. <You don't want to run all this flow over/through the mud/sump portion> Regarding the closed loop would 4 Â½" outlets seem appropriate here? (about 125gph per outlet? But with lowered 45 deg nozzle size to provide good flow) I was hoping for more outlets so I could direct against each other to provide random flow, Tank by the way will be a 24" cube (about 50 US gallon/200 litres) with soft corals, fish etc - nothing too challenging yet. <Likely will be fine> Will I still be looking at about 500gph/2000lph actual output? <Mmm, likely 400 gph will be closer> Does this sound workable or should I be concerned about lack of flow/current here? An in tank pump with outlets in the back corners could be considered in addition - or indeed any other solution is a possibility as I haven't even ordered the tank yet let alone pumps etc!! Cheers Chris <And to you. Bob Fenner>

Manifold Flow...Why so Weak? - 09/26/05 Hi crew, <<Evening>> Can you give me some assistance with my manifold problem? <<Shall try>> Setup is: 60x24x24 display, 48x24x20 sump with 2 x 1.5" overflows from display into skimmer/heater chamber, middle chamber is a fuge and final chamber is the return pump which is an Aquamedic 6500. My guess is the two overflows will give me approximately 1000gph <<A reasonable volume to handle efficiently, yes.>>, the return pump is around 1400gph and the head is approximately 4 feet to my closed loop manifold. The manifold is all in 1" pvc pipe with 10 outlets. I put too many in so that I could play around. <<smart>> Only problem is that closing off certain outlets does not make an awful difference to my manifold flow, it's strong at the pump end and weak at the other. <<This is likely due to the outlets being too large. Try adding reducer bushings to bring the outlets down to 3/4" or even 1/2" to increase resistance/velocity. Also, be aware that you need about 300-350 gph per 1/2" nozzle for effective flow. That means if your estimating 1000 gph from your pump (after head, plumbing turns, etc.), you only have enough flow for THREE outlets.>> The return pump comes in at the back left corner of the manifold, Would moving the pump to the centre of the manifold make any difference? <<Little...if any.>> I guess if I reduce the outlets to say 0.5" this should help. <> Can you give me some advice please. I'm at work and should be working but I just seem to be mulling over the manifold flow problem. Cheers DaveG (UK) <<No need to fret mate, reduce the outlets as you have surmised, and consider the possibility of getting a bigger/more powerful pump. Regards, EricR>>

Water Flow/Outlet Size And Closed Loops - 09/04/05 Hello Again, <<Howdy>> So happy you guys are there! <<And happy to be here!>> I just tested my system and am not happy with my return water flow. <<uh oh>> I have a Mag 36 in the sump returning water to the tank by 1" line thru back upper drilled hole in tank, this then goes to 3/4" loop around the top of tank and completes a loop. <<ok>> I have 7 'T' outlets on this loop. Only the first outlet gets any good flow, the rest slowly get less as it goes around the loop. I have about 10 ft. of head, even with that I should have 1800 gph. Did I hook it up wrong. I have 3 1.5" outputs going to sump with horizontal skimmer box, the flow seems to be there because the outflows are working good. <<I have no doubt the flow "volume" is there...the problem is in the application. To have sufficient "force" to be effective, a 3/4" outlet on a closed-loop requires from 600-700 gph of flow...conversely, a 1/2" outlet requires only about 300 gph. Assuming your flow calculation is correct, you only have enough flow for three 3/4" outlets...at best. To keep from having to cap off the majority of your outlets, use reducer bushings to reduce the outlets to 1/2" and employ a maximum of 5 or 6 outlets.>> Thank you in advance, Dan P <<Regards, EricR>>

Closed Loop W/Manifold Plumbing Design - 08/13/05 Hello crew, <<Evening>> I'm doing an open top 180G (6'x2'x2'). I want to do a CL with a manifold under the DSB. I have the tank drilled for two 1.5" bulkheads for this CL. As for pumps, I'm considering one of the Reeflo models (Dart, Barracuda or Hammerhead). I know we can't get into exact head loss calc.s etc. but hopefully you can help me based on your experience. I want to be able to have SPS and any other high flow critter I'm interested in. <<okie dokie>> While considering my CL question below, keep in mind that I want to try to get about 800-1000 gph from my sump return running through two Penductors (which supposedly should equate to approx. 3000-4000 gph they say although I'm a little skeptical of this number). <<As am I. Have seen these (on a 180), just not convinced the flow is increased by this large a volume.>> So starting with a 1.5" bulkhead into the tank I could tee to a 1" loop or keep it 1.5". I think I have plenty of room in the DSB to do a 1.5" manifold if it will be better. <<Not much (if any) advantage to keeping the 1 1/2" diameter here...would plumb 1" just to save on PVC costs/ease of handling if nothing else.>> My main question though is how many nozzles (size and diameter) to run off the loop. They will have some LocLine to allow direction adjustment. Assuming approx. 4' head loss a Dart would do about 2900 gph for 160 watts, a Barracuda would do about 3900 gph at 315 watts, and a Hammerhead would do about 5500 gph at about 370 watts. I don't want to have too few CL nozzles and have them act like jet streams, but I don't want to have a forest of nozzles sticking out of my sand either! I appreciate any advice you can give me... <<Nozzle size/quantity will depend on the pump you choose. You have some figuring/deciding to do here mate. Decide how many nozzles you want...figure 350 gph per 1/2" nozzle and 550 gph per 3/4" nozzle...divide these figures in to the flow rates for the three pumps...whichever figure comes closest to the number of nozzles you want...wallah! Thanks, Randy <<Regards, EricR>> Get That Jet Stream - 08/13/05 Can you PLEASE correct my spelling of "get stream" to "jet stream" in the last paragraph of my previous email if you put it on your FAQ pages? LOL If you can that would be nice, if not, oh well, I'll just have to look like a goofball... -Thanks! Randy <<No worries my friend...took care of it. Funny how the brain works/reads/disconnects sometimes, eh? EricR>>

Closed Loop W/Manifold Plumbing Design II - 08/14/05 Thanks for the advice to assume 350 gph per 1/2" nozzle and 550 gph per 3/4" nozzle for my CL manifold. Would you care to estimate a rough head loss number for a system like this? Is 4ft reasonable or is there a rough number per nozzle I can assume? Thanks and have a great evening, Randy <<Aside from the actual vertical run, I would add a foot of head for each 90-degree elbow, a foot of head for every ten feet of horizontal run, and for good measure throw in another foot of head for the nozzles (combined)...yep, eats up flow rates in a hurry. Do buy enough material to build a couple different configurations if necessary and test these for desired performance before making a permanent installation. EricR>>

Closed loop on timer 8/3/05 Hello, I had a question some other reefer asked me about my closed loop set up and I am now curious to others opinions. I have a Iwaki (2100 gph) plumbed with 1 inch pvc. I have the pump on a timer that shuts down shortly after lights out and comes on just before lights on. The question is this: Will the water in the closed loop become stale , could this become a problem? <Not likely...> I also have 2 Tunze streams running 24/7 and a mag 12 as my return from the sump that runs 24/7, the tank is 180 gallon with a 55 g refugium and a separate sump. I have not noticed any problems but would like to prevent any if this could become one. Thanks again for all your help and happy reefing. Mike <Not much nutrient, things to go wrong in the small amount of volume, time... Bob Fenner>

Will a closed loop for circulation really only work if you have the 7/26/05 water coming to the pump from either a hole in the back of the tank (below water line) or the bottom of the tank? That is, am I wrong that a line that runs over the tank edge to the pump would not work, or work well, since a loss of power would break the siphon, for lack of a better word, to the intake of the pump. Am I wrong here? <Hi Jon, please see this link: http://melevsreef.com/closedloop.html - Ali> Water Return Manifold 7/19/05 Dear WWM Crew, I just read over Anthony's article on water return manifolds and had a few questions regarding it. First, I gathered that it is usually used for larger systems but was wondering if it can also be used with smaller aquariums (ex. my 30g reef) <Yes> I'm sure it could be adapted to my aquarium but for a 30 gallon reef that will be holding some medium current LPS corals how many tee outlets should I use? <Four, six...> And finally should I add any special nozzles to the tees for better flow? <Could... I like the "Loc" types for ease of directing... there are threaded (male) bases available... to fit PVC female...> That's all I need to know for now. Oh, and before I forget, please give my regards to Anthony for a very well written and informing article. Thanks, Andrew <Will do. Bob Fenner>

Overflows vs. Closed Loop 7/17/05 Good day, <And you> I really should be charged for all the questions I have been asking lately. so please feel free to let me know where I should deposit the money and how much :-) <We never turn down the cash!> At the moment I wish I never heard of "closed loops", because I am really battling with this. I'm setting up a new 150 Gallon reef tank and have really struggled a lot to sort out the water circulation. For my overflows I have 2 x 1.5inch bulkhead drains (inside diameter). From the sump I have a pump that sends about 1500gph into 2 x SCWD for the return. The overflows seem to handle this quite easily, with no problems so far. The problem I have is with the additional circulation. My original plan was to use an "over the top" configuration for a closed loop, where I don't have to use drilled holes. I'm finding the plumbing for the closed loop very difficult to do, the tank braces and "lips" makes life a little difficult with the "over the top" type setup, I'm finding it very hard to find the proper parts, ball valves etc. and I also have some space problems below my tank.. I'm very frustrated at the moment. <Seems so> So now I'm thinking of drilling an additional 2 x 1.5" holes to cater for the intake of the closed loop. At least this will eliminate the need for "over the top intakes". The one thing I would really like your opinion on is the following - The one place I do have a lot of space in is the "return chamber" in my sump. The total sump size is about 65 gallons, with the return chamber on its own taking up almost half of that. So the one option I was considering is - instead of using the 2 additional holes for a closed loop, rather add them to my current overflows and add the second pump to my sump. This way I will have 3000gph going through my sump/overflows with 2 return pumps and no need for the ball valves and other things I've been struggling with so much on the closed loop. I can split the overflow lines so that only part of the 3000gph goes through my refugium area and skimmer and the rest straight into my pump return chamber, so I'm not much worried about sending too much water through my refugium. Do you think the option of using more overflows with 2 strong return pumps instead of a closed loop for 3000gph be a bad idea? <Mmm, no> Should I rather bite the bullet and continue my struggles to get the closed loop going? <Up to you of course> Is 4 x 1.5" holes too much for a 150Gallon tank ? <Mmm, no> Ps. I will connect the second pump to another 2 x SCWD, so the actual flow rate will be a bit less than 3000gph. <Okay> Any advice will really be appreciated. <Perhaps a good idea to "step away" from this project for a while... Come on out to HI next month and go diving with me... all will seem clearer with a bit of a holiday away. Bob Fenner> Many Thanks Chris Re: Overflows vs. Closed Loop 7/17/05 Hi Bob, <Chris> Thanks for the reply. Diving with you sounds like a great idea, but unfortunately I'm thousands on miles away here in South Africa. <Ahh, our mate who has lived with us a dozen years is on a walk-about visiting in Swaziland... where he and his brother had a farm implement biz... till it was "nationalized"...> Have fun Chris <Mmm, do keep the "break" in mind... and re travel... "you get on a plane, you get off a plane"... Tis an exceedingly small planet my friend. Bob Fenner>

Return Manifold pump selection 7/7/05 I love this resource you guys have and thank you very much for the wealth of information. I'm building a new 120 gal. FOWLR acrylic aquarium for my shop and since I'm having it built I want to do it the right way first. I may eventually put inverts and easy hardy corals in later so I'm trying to plan for it now. I've been reading up as much as I can in Anthony's book "Book of Coral Propagation" (great book) and am awaiting my copy of the "Reef Invertebrates" book. I'm currently picking out my equipment and deciding how I'm going to do the plumbing for a 120 gal acrylic tank. I would like to incorporate the "Shelf overflow" idea that is in the Book of Coral Propagation" (illus. on pg.42). <Mmm, please read (and read!) here: http://www.wetwebmedia.com/pbh2oret.htm and the linked files at top/s... Bob Fenner> Sumpless Closed Loop Manifold Hi WWM Crew, <Glenn> I have a 75Gallon tank that I had drilled when I converted to DSB/Live rock filtration. I had only one drain installed and it cannot handle a more powerful pump return than 375 Gallons. This drains to a 20Gallon sump/refugium. The rest of the circulation is handled by 4 MaxiJet power heads suction cupped to the wall (All these pumps combined add up to 1000GPH). Unfortunately, the have been getting loose lately and creating snow storm in my tank. I'm fed up and want to try a manifold. But I cannot use the existing drain and I don't want to take the tank down to drill another hole. <Can, could go "over the top", edge of the aquarium...> The only option I can think of is an internal pump, like a Mag 12 or 18. How do I place this pump in the tank and still avoid my fish and sand getting sucked up. <Careful screening> Last year, I lost my Dragon Wrasse to an uncovered intake ,on a powerhead. Very disturbing site to see you favorite fish half in and out of a powerhead. (He was already sick though, I think that is why he was sucked in.) Thanks, Glenn <Do take a read through our site re manifolds, plumbing... a few options for you here... using pump/s outside the tank. Best. Bob Fenner>

Re: Sumpless Closed Loop Manifold, powerhead use 07/01/05 Bob, <Yes> Thanks for the reply. I've decided to go with an internal powerhead. After reading many FAQs and other forum threads, I've purchased a Tunze Stream. I went with the 6060, which cannot use a controller, to vary output. I'm amazed it can move more than 5 times the volume of water using less electricity than the Maxi Jet 1200's. <A very nice product> I've directed the pump to partially reflect off the front pane of my 75 aquarium. I'm hoping this will spread the flow in multiple directions. <Should> Should I run this pump 24/7 or power it off at night and run just a few maxi jets and the return pump at night? Thanks, Glenn <I'd leave all running continuously. Bob Fenner>

Closed Loop Hey Crew! <Ben> I've Googled and surfed and can't seem to find a simple definition for a "Closed Loop" circulation system and/or a diagram of the principle. Please Help! Thank You, Benjamin <Mmm, some pix here: http://www.wetwebmedia.com/pbh2oret.htm and the linked files above. This is a "closed" as in not open (to the air) recirculation system for moving water around with a motive force (pump) located outside an aquatic system. Bob Fenner>

Re: Closed Loop Reply to Bob Bob: <Ben> Went to the link you suggested and all I saw was a pic of a closed loop manifold. <Please see the rest of the response... the linked (Related FAQs) files above...> I think my question regards closed loop for recirculation of water in tank for flow purposes. Pumped into tank and pumped out of tank <Mmm, no. Not pumped out... gravity, siphon fed> on a separate pump ergo CLOSED LOOP? If I am correct then how does one plumb for sump/refuge/protein skimmer when utilizing a closed loop system for increased flow? <Separately... not on or with a closed manifold> Strange to tell but I've been bopping along thinking closed loop =no fresh sea water coming in from ocean hence water pumped into tank/overflow out of tank to sump= closed system. But it seems I have misinformed myself and wanted to assume nothing. Thank You Benjamin <Sorry for the confusion. Take a look at the Related FAQs files. Bob Fenner>

Re: Closed Loop continued Bob: <Ben again> Ok, I think I have a handle on what a closed loop system is now. One pump is dedicated to taking water from the tank and returns it to the tank with no stops (processes in-between). Purpose being internal tank FLOW (turbulence?). Then another pump returns water to the tank from the sump, the tank overflows into a return system and back to the sump it goes. Am I correct? <Yes> If I am on the right track then I have some concerns. I was taken by your idea of a weir (a glass plate in the back of the tank fixed at a 45 degree angle to the back plate) mainly for its ability to skim the surface efficiently and provide QUALITY protein rich water for the skimmer. My general plan is to feed the tank from the sump with 4 2" pipes .(one of which would be reduced to 1" or 1.5" for a return manifold and another 1" branch off of a different 2" for refuge return) and overflow drained with 4 2" pipes. Powered by a Super Amp Master 7500 or something close to its capacity of 6900 gph @ 4' head with 2" inlet and outlet. <This is a big pump...> Tank would be 180gal with a 100 gal sump and an independent 55 gal refuge (all with 6"DSB) mounted to the side but above the main tank My guesstimate is that total water displacement will be aprox.. 40%, leaving aprox. 200 gal. of actual water capacity. Estimated turnover to be somewhere in the 28 to 34 times per hour range. With that information as a background MY QUESTIONS ARE: 1) Since I've never seen a configuration like this actually run what is your sense of the flow and turbulence that will be produced in the tank. Will the critters and rocks be flyin' around or just happy in the current? <With "proper", "adequate" dispersion the latter. Not much of this water is going through the refugium I hope> 2) Will such turbulence defeat the proclivity of protein and other waste products from residing at the top of the water thus defeating the beautiful idea of quality water for the skimmer? <Not practically... such phobic molecules make their way past, into fractionators in due time in any, all cases> 3) Would such a turnover eliminate the need for a closed loop system? <Likely so... though I would rig a manifold for distribution of the return water> 4) Would one 2" fixture (the pump) feeding 4 2" pipes greatly reduce pressure? If so perhaps I should think of only 3 or 2? <I would use one... return pipe... two inch bushed down at the over or through tank fitting to one inch tees... Do take a read through our plumbing article, FAQs files before committing to a given plan here. Bob Fenner> Thank You Very Much, Benjamin

Drain Size and Noise...(Understand?...Soon Grasshopper) - 06/17/05 Ah. Now I understand. How much noise will there be with two 1.5" drains to the sump? <<If you're turning 1500 gph?...the larger diameter will help with air entrainment/flushing, but I think it would still be quite noisy. You're still processing/dropping a lot of water in to your sump. My suggestion would be to use just one of those 750 gph pumps for sump return.>> So there shouldn't be any noise associated with my closed loop system if I have a 1" gravity drain (hole at bottom of tank) that leads DIRECTLY to the 1200 gph pump, and little or no need for "dialing back" the return with a gate valve? (Will still have a gate valve on the return just in case) <<Don't think of the return for the closed loop as a gravity drain...it's not...it is the pump "intake" for the closed-loop. And no, you wont need to dial back the pump. That's the beauty of the closed-loop...you're pumping "in" exactly what you're pumping "out.">> K <<Do a key-word search of the WWM site for "closed-loop"...lot's more info for your edification. Regards, Eric R.>>

- Planning Stages and Questions, Questions, Questions - Good morning everyone! Thank you for such a great resource. Too great! My head is about to explode from information overload. Anyway, I'm planning a reef tank / Palau biotope for my office. I inherited a 95 gallon corner hex tank. I've attached a diagram of the tank from above. I read Mr. Calfo's article on a closed loop manifold and have decided that is the way I want to go. (my design for that is the grey part in the attached image). After reading a lot, I changed my pump choice for the closed loop system from a Iwaki WMD20RLXT (540 gph) to a WMD40RLXT (1200 gph). Seems like a lot, but hey, more is better, right? <In the case of circulation, yes.> So, my questions... Due to the non-standard shape of the tank, I've designed 8 outlets. I initially decided on 3/4" PVC, but think I should go with 1". Too many outlets? Correct diameter pipe? <3/4" might be better around the rim of the tank as should keep pressure consistent across the nozzles. Would still plumb up to the manifold with 1". Would encourage you to experiment with freshwater before filling with salt. This would allow you to swap out sizes if 3/4" doesn't work.> Also, lighting. I'm planning on a few fish (big list, trying to whittle it down), soft corals and mushrooms. Since the aquarium is 24" deep, I am thinking I need MHs (although I really don't want to). <For soft corals and mushrooms, you don't need metal halides.> The problem is how to arrange the lights in the built in hood for the best coverage. Is one 24" fixture perpendicular to the display area enough? <Yes, should be fine.> (assuming several lamps, adequate intensity, etc.) What about the back half of the tank? <Are you going to be viewing this area?> I could probably put in a small fixture that runs perpendicular to the main fixture in the back half of the tank. <You could, would not harm anything if you did.> Any ideas? <Sounds fine to me.> Also, June IMAC in Chicago. I live there. This is an invitation to dinner for any of the WWM crew that's going to be there. I'm sure you will be very busy here but if you happen to have some spare time and desire a good meal... You guys do a great job and deserve to be rewarded as often as possible by the people who use your site every day! Especially after reading a recent e-mail from a not very pleasant person who didn't like the help he received. What a jerk! <Happens - cannot please 100% of people 100% of the time.> Complaining about a free service that does everything above and beyond. I dare that reader to find a pay service / store / person that can do any better. Thanks for everything. Rich
<Cheers,

- Strange Pump Noise - Guys, I have a slight problem with a new Panworld 100PX-X pump that is hooked into my closed loop. The pump has a 1" inlet and 1" outlet... but I'm running 1 1/2" hose down to the pump to make sure it doesn't cavitate. I have a 1" hose coming out of the pump up to my closed loop manifold. I assure you the pump is completely isolated from vibration type noise. I have attached a picture to show you my setup. My problem is that there is a slight intermittent spitting sound coming from the impeller portion of the pump. <Sounds like you're drawing air every so often.> It never really stops, but it's a random noise (not cyclic). I'm sure its not cavitation, because there are no bubbles going down into pump inlet (I can see through the clear hose). <They wouldn't have to be very large.> The pump has plenty of water to work with. Premium Aquatics told me to take apart the pump and inspect it for something inside it... but I'm only running freshwater for my test setup... no sand, coral, etc. I took it apart and found nothing out of the ordinary. After assembling it and running it again... the same spitting sound was there. Moving the pump around does not affect the noise. <Would suggest you use the valve on the output side to throttle the pump back ever so slightly and see if this noise still occurs.> Any idea what it might be? <Beyond air in the line, no.> Have you ran into this issue before? <Not on my own systems.> (By the way, I'm out of the 30 day internet warranty period... and I'm just curious to what could be causing this because I think I've done everything right with the plumbing) Thanks, Cody <Cheers, J -- >
- Follow-up on Strange Pump Noise - Follow up after some testing... After reading more WWM FAQ's, I stumbled on the fact that might pump might still be cavitating even though I have enough water for the pump?? <Can happen.> I don't understand this... <Air induction in the plumbing.> But I guess it is cavitation that I'm hearing even though there isn't any air to cause cavitation. I have 1200 GPH running through my closed loop manifold to 4 evenly spaced LocLine nozzle outlets (300GPH each). It works great along with my (2) 300GPH return nozzles for a 75 gal tank. What's strange is that I blocked one of the nozzles with my finger thus increasing the resistance to the pump and the spitting noise went away instantly. Why would more resistance to the pump stop the cavitation noise?? <Supply versus demand.> It seems like it would be just the opposite. Along the same lines I closed off part of my pump outlet to the manifold using the ball valve. After adjusting it to put more load on the pump, the spitting noise once again stopped. Can you guys explain this madness? I surely don't want to only have 3 closed loop manifold nozzles although I guess I could. <I'd just close the ball valve a little bit...> And I'm not sure its a good idea to restrict the pump outlet with the ball valve. <Will only up your electric bill a little bit - will not harm the pump.> I am confused here. <The pump is just driving the system more than it can actually take in water. This may seem counter intuitive because you increased the inlet side, but you just have to take my word for it that this is in fact possible. The increased diameter of plumbing right before the pump could be inducing turbulence at the restriction and this is what is causing the cavitation. Throttling back on the supply side is just reducing this turbulence.> Thanks, <Cheers, J -- >
- Closed Loop Bubble Trouble? - Hello Good People, John Here; This is not a question but rather I was moved to provide input regarding a question from yesterday where the individual had pump noise/cavitation trouble on a closed-loop circulation system. I myself have tried to get a closed loop system going using a MAG350 (as a test bed, since I had one) and later with a MAG950 to provide the desired circulation with my final plumbing. The plumbing consisted of a pipe going up and over the rim to the pump, through a SCWD and two lines back to the tank. What I found, and what my limited knowledge of fluid dynamics suggests, is that if your pump draws water faster than it would flow by gravity, a low pressure is imparted on the water. Since the solubility of gas in water is proportional to pressure, any dissolved gases in the water may come out of solution in the form of bubbles (akin to opening a bottle of soda pop) which will cause pump cavitation and, in my case, bubbles in the discharge. The solution is to throttle the pump discharge valve (reducing flow and tank turnover) or increase the diameter of the suction line (preferred). This idea was proven nicely with the MAG350 which performed well with a 1" suction line whereas it cavitated with 3/4 or 1/2" line. Alas, with the 950, a 1.5" suction line was required and the height of the elbow above the tank (un-drilled, sigh) causes a sufficient temporary pressure drop at the elbow to cause the air to come out of solution regardless. So far, I haven't figured a way around this and am still using power heads. Some kind of wide flat elbow or two smaller ones in parallel may work, but I haven't tried it yet. <Thanks for sharing.> JT <Cheers, J -- >

Closed loop and sump questions Greeting & Salutations, < Good morning. > I just read a couple of articles Anthony has written about closed loop systems and water flow and would like to ask your opinion on a couple of items.< Go right ahead. > a) If I use a an external canister filter e.g. Rena Filstar XP2 (I will also use it for chemical filtration) and "extend" the return outlet across the perimeter of the tank using elbows would I have effectively created a manifold closed loop system. < Yep, you would have. The only downside I can see is that it will be quite weak. You would be better with a large pump. > b) After much deliberation I have decided to create a separate refugium which will have a gravity fed outlet into the sump. I have 2 options of getting water to the refugium a) have a small pump to feed it from the sump. b) Attach a Y piece to my hang on overflow box and a attach 2 flexible hoses, one the sump and the other to the refugium. I am leaning towards option a due to flow rate. What is your preference? < Tough question. First I would make sure they new refugium can handle a very large overflow. If you "T" off your return line it is possible a lot of the water flow will go to the refugium. Okay as for the two options, they both seem fine to me. I would probably prefer to not add another pump in the refugium system. I would rather T off the return line. If you do add a pump I would add another pump in the sump to the main tank. > c) One of my wet dry filters will be converted into a sump for my tank. Will I get extra denitrification capabilities if I place some live rock in the bio chamber area? < Absolutely. This is a very good idea. > Can I grow macro-algae without a substrate - creating a second mini refugium (I know I can get algae on the rocks) < Without substrate? Well with some Chaetomorpha you may be able to, but substrate would certainly help. > d) Do you know when Anthony & Bob's new book will be out and where I can order it? e) I plan to incorporate an auto top-off system. Should my reservoir be filled with RO/DI water or saltwater? < RO/DI water!!! > f) I looked through the FAQs and even though there is much on addressing noise issues I could not find any advice for softening the noise in the sump after the a wet dry filter has been converted into a sump/refugium and the drip plate has been removed - I still would like use the filter covers. Any advice on this or please point me to the right link. < Hmmmm, not sure. If you can extend your return line all the way down into the sump water (so it doesn't splash down) you shouldn't have any noise problems. > Finally, I have spent a lot of time reading the FAQs and it seems that - especially in regards to a FOWLR- weekly cleaning/maintenance, weekly water changes and patience e.g. using quarantine tanks, proper acclimation/cycling/curing etc. can get me around using most water additives/supplements and commercial substrates and avoid most of the issues being discussed. I believe in the KISS (Keep It Simple Stupid) methodology. Now, I know reef systems are a different animal- or am I simply missing the boat i.e. the complexity of this wonderful hobby (and expense)? <To me, a reef tank is much easier to keep and far less trouble than a FOWLR tank. The filtration issues and stress to the fish are just not as important in my opinion. So I don't think I would ever set up another FOWLR tank. > Thanks with much admiration < Good luck. > < Blundell >

Closed loop and Return Manifold Good day, <And to you> I have spend the last 2 days reading through your articles and FAQs on return manifolds and closed loops and I'm a little overwhelmed by all the information available. English is not my first language and some of the terms is a little hard for me to comprehend, so I was hoping you would be willing to assist me with something that you have probably assisted many many other people already. I'm in the process of planning my new reef tank of approximately 150 gallons and would like to design a closed loop manifold for water movement/circulation. The tank is not built yet, so I can decide now how many holes to drill and where. I'm having difficulties understanding the design of the inlet to the closed loop. If I understand correctly, I can either use an "over the side" pipe into the tank or a drilled holed in the tank for this. In both cases the pump will 'suck' water from the tank via the inlet and pump it back via the return manifold (correct ?). <Yes, correct> In both cases I need to use a 'strainer', which is almost like a little filter on the end of the inlet to prevent the pump from sucking in fish. Which one of these two methods would you prefer ? <Either will work> If I understand the drilled method correctly, this is simply a hole 2-4inches below the water surface that is connected to a pvc pipe on the outside, which immediately turns 90 degrees downward to go to the pump below (is this what they call a bulkhead?). <One name, yes... also known as a through-hull fitting, gas jacket fitting...> Is one advantage with the drilled method perhaps that the pump does not have to be primed ? <Yes> If you don't mind, there is one last question - my return pump for the closed loop will probably be at ground level, which means it will have to pump the water upwards around 5-6feet, which means that even if I have a pump that can do 3000Gallons/Hour, it will probably only do about half of that or something, so I probably need to have two of the closed loops installed if I want to turn the water over 20times, one for each side of the tank? <Actually, with the lines filled, there is little head pressure loss> I feel really guilty sending you these questions, because I can just imagine how many questions like this you have to deal with on a daily basis, but at the moment I feel that my head is going to explode after 10 hours of reading FAQs. Words like 'bulkhead' is not the kind of thing I'm exposed to here in South Africa very often :-) <No worries... A friend who has lived with us a dozen years is from Swaziland... I grew up in the Philippines and Japan... lots of cross-cultural experience> Thanks in advance Chris <Welcome my jabulani. Bob Fenner>

Pump Sizing/Plumbing For A Teed Manifold - 05/21/05 Hello, <Hello Frank> I have a 135 gallon reef tank, currently running a Gen-X 1190 GPH return, and I have two 1-inch drains in the lower back of the system feeding into the sump. <Couple thoughts/opinions here Frank. First - Be careful not to overestimate what your drains can handle and plan accordingly. Many claim 600 gph for a 1" drain, and under ideal circumstances it will probably handle it (albeit noisily), but I've found that a "safe" flow rate for this size drain is about half of what's usually recommended. Be aware that flow will eventually start to restrict due to growth of algae and cryptic organisms within the opening/drain pipe. Second - You mention the drains are installed in the "lower" back. Unless you have some type of riser pipe/overflow box installed, your tank will drain to this point when the pump is off.> My question has multiple parts: 1) Is my Gen-X giving a sufficient rate of turnover to my tank in general, and is it powerful enough to give decent flow to a teed manifold with six or so outlets, enough that I can forget about power heads? <On its own, no, even before accounting for head loss. Some suggest a minimum of 10x total tank volume for flow, I feel more is better...20x plus. When figuring number/size of outlets for the manifold figure 400+ gph for each 1/2" outlet and 800+ gph for each 3/4" outlet on the manifold. Its my opinion your current pump would limit you to two 1/2" outlets on the manifold. With a proper pump/manifold design (much covered in the FAQs), yes, you will be able to forgo power heads.> 2) If not, what should I upgrade to and will this require additional holes cut in the tank for drainage? <Assuming six 1/2" outlets, you're looking at a pump in the 3000 gph range before head loss. As for your drainage holes, I would plumb the two 1" drains directly to the pump and create a "closed-loop with the manifold. You really don't want to try to push this volume of water through your sump. Add another 1" drain and plumb the MAG 5 for your sump return.> 3) I am running a 500 GPH Mag 5 (and plan to add a second Mag 5) inside the tank at the moment. Between this and the return pump am I giving respectable (I know it is not ideal) water turnover for the size of my system? <Could be made to work, though the manifold is a much better idea. Be sure to adjust all flow output to interact in a random turbulent fashion.> Lastly, I know the answer to this could potentially fit under multiple categories on your website, could you please post it under Plumbing 18 FAQ so I can find it easily. Much Appreciated, Frank Janes <Regards, Eric Russell>

Manifold I'm wanting to put a manifold on my 55 gallon glass aquarium, I ordered a Sen 900ga specs can be found at www.wonbrothers.com, then selecting pumps, Sen 900ga. The question I would like answered, is would it be wise to tee off the pump sitting inline on shelf behind tank plugged in UPS, one being to the manifold with 2 outlets on back with 2 on front directed at same location, 1 centered on each short side. And the other to the Remora Pro skimmer I already have with the Mag 3 pump. I ask this since Aqua C has remarked that a Sen 7 pump could be used for even more efficiency. The Sen 900 seems like it would have enough water flow to run the manifold at 10+ times gallons of tank to the manifold alone, and the skimmer without a problem. There is 60 lbs live rock, about 5" -6" of sand. Also have a penguin 350 and Fluval 204 with uv light on its output, that may go to a 30 gallon QT tank. Also would like to know, what size pvc to put around the rim and which size outlets that I should use. I'm guessing 3/4" pipe around with 1/2" outlets. <Likely would go with just half inch all the way around... no more than the discharge side/volute of your pump... and ideally have all plastic valves or other simple means (drilled slip plugs) to restrict the discharge points/outlets in the tank... push these in so they can be wiggled out (likely with pliers) should you like to change them> I was looking for the Sen 700, but the 900 is only $10 more. What a bargain if it is dependable. <You'll soon know> Another reason, I ask this, is pumps in the tank don't exactly look like something that would be in the environment we're trying to simulate. As well as removing a heat source. I have heaters for that, and really don't want to have to purchase a chiller. Also, I'd love to get a Pearly or Bluespot Jawfish, and lawnmower blenny. Currently, I have 2 Ocellaris clown, 1 lipstick tang?, <A Naso lituratus? This tank is too small for this species> 1 firefish goby, 1 green chromis (timid), 1 mild mannered yellow tail damsel (returned aggressive 1), 1 Singapore Angel. If I put the Jawfish, I'll get a bag of crushed coral and put in one end of tank or scattered about? I suppose with this fish, I'd have to leave an area without much rockscape for an "open" area of tank and make sure top has NO openings. <Mmm, keep reading, scheming... you'll do fine. Bob Fenner>

Loop Manifold questions 4/21/04 You really do burn the midnight oil! <At times like now (post and pre-travel)... yes, very much so <G>> Thanks for your dedication and suggestions! I have a couple of follow-up's. This tank will start off as FOWLR, but since I'm constructing it, I want to plan for eventually going reef with it. If I dedicate a pump to the closed loop, then I wouldn't need to go with 3 2" upper back wall bulkheads as these were intended to provide enough drainage for high turnover through the sump to display. In other words, would you simply put a pump behind the back wall display (below intended water level) with one bulkhead for input and then connect to the perimeter loop? <Yes... this works best for most folks and is exactly what I am doing for the next/latest personal display tank of my own being set up> If I only have one input to loop pump, fully submerged bulkhead, what would be the impact on noise level, or would you recommend the loop suction side of bulkhead not be fully submerged for maximum silence? <Hmm... I'm really not sure what you are asking, mate? If the pump draw is flooded (below the water line and gravity overflowed)... then the noise of the closed loop with effluents at or slightly under the water surface will be minimal - relatively speaking> Would you still recommend a sump? <Yes... they are quite convenient for so many reasons> What sump to display turnover is recommended? <Slow is OK here to minimize salt creep, noise, etc: 5-10 X would be fine> Any recommendations on a dedicated loop pump (which in this scenario would have close to 0 head)? <Iwaki (Japanese made) is still my first choice... then Sequence pumps are my second choice presently. kindly, Anthony>

Closed Loop Manifold... Good morning! My husband and I are preparing to set up this closed loop manifold (maybe just one pipe in back across the whole back) in our 90 gallon acrylic. We checked with LFS man who had the tank made for us. He said that all drilled holes and bulkheads can handle the new GPH; we just have to change what he called the spur fitting. We are considering either the PondmasterÂ¹s Mag Drive 18 or 24. With one, considering the overhead, it will actually be about 1200 GPH and the other, 1800 GPH. So 10 x's or 20 x's the turnover... hmmmm..? Questions are: 1. Anthony states in his article that 6 tees for return water is max for 100 gallon tank. Could I have more? <Yes... of course, any given flow rate, pressure will be diminished per outlet in terms of outflow with increasing number> 2. My husband talked about using a smaller PVC pipe to "pinch" the water to increase flow. Much like a plumbed house. Main line coming in is bigger and then goes to smaller to increase the pressure. Is this o.k.? <Yes... a good idea> 3. And basically, how do you make sure you are utilizing the max GPH and not causing back pressure because you used too few holes? How do you make sure you donÂ¹t have too many holes thereby making the pressure too gentle coming out and thereby losing effectiveness of the reason for manifold? <Mmm, can be done mathematically or by assay (actual practice)... my advice is to go the latter route... Not gluing/solventing pipe, fittings on the inside of the tank... looking at the resultant flow with the pump on, tank filled about all the way... experimenting with changing out diameter, number of fittings... until you have about what you want, what you're going to get... taking all back out, apart, drying, gluing together...> The rest of the information provided seems easy enough. These are my only questions....except, as you answer them I'll probably find more! Ha. Thanks. From MI <Welcome. Bob Fenner>

Closed Loop Manifold 4/14/05 Anthony, I'm planning to build an aquarium out of glass 72"L x 30"Wx 24"H 1/2" glass. I have planned to use 3 2" bulkheads (top back wall of tank) draining to a sump. I plan to use a Sequence Hammerhead for the return pump (approx head 18ft). Sequence suggested 2" piping off the return (in order to maximize flow vs. pressure)... <Yes... understood> ...which means I would have to go from 1.5" (discharge) to 2" up to the tank at which point I wanted to do a closed loop around perimeter of tank. <Good> I have been told that the water level should not be over the 2" bulkheads. In other words maybe half up the bulkhead to reduce noise. <Quite correct! For safe running/operation, do not overdrive the drains to the point where their running level is half of their capacity or greater (too noisy if nothing else)> My problem and hence questions have to do with how to configure the piping. <The Closed loop pump in this case should be on its own drilled loop, and not tied into the sump> I have to put bracing all the way around the interior top of tank, but also take into account room to place the 2" pipe going around the perimeter (which will reduce to 3/4" for outlets), and try to keep the bulkheads slightly above the intended water level (otherwise the loop will run into the bulkhead baskets or bracing or.....), and also consider how to put a glass cover (lid/lids) over this whole set up. What suggestions, concerns, changes, etc might you suggest to make this work? <From what little information is provided, I see no problems> Also, any suggestions on where to obtain black silicon for putting together an aquarium? <Google until you can't Google no more <G>. And the big mail order companies perhaps like MarineDepot.com, CustomAquatic.com, ThatFishPlace.com, etc.> Many thanks, you guys are the best! <Kindly, Anthony>

- About Closed Loops - Would like to ask about closed loop. <Ok.> I have 70x24x23 inch tank and would like to do a closed loop. I have bought the pump (Senso), which is about 7500 liters per hour, would like to know that it is too strong for the closed loop. I have seen one pic from http://www.wetwebmedia.com/pbfaq12mar.htm - should I do it the same way? <With some caveats - you need to make sure you have valves on the input and return sides of the pump. I'm assuming you don't have bulkheads in your tank for the closed loop, which means you'd use an up-and-over type of feed and return lines, which will both create a siphon which would need to be shut off if you decide to clean or service the pump.> The return pump is 3500 LPH. Is it affect the closed loop? <Should be fine.> Thank you very much, Bing <Cheers, J -- >

Water flow options: manifolds 3/16/05 Dear Anthony <Cheers, mate> I read with interest your article on flow in a reef tank. I, like most aquarists with an advanced set-up have more than my fair share of Maxi jet powerheads in the tank. I have however got a very large Eheim 1080 with a return overflow box servicing most of the flow within the tank so flow is quite turbulent (on the return side of the tank). I do however have dead spots which I have removed (not very successfully) with the use of an array of powerheads. <Indeed... that's a challenging way to go about it> Do you know of a method of attaching LocLine modular hose to one of these buggers? If not then a pump that I can purchase here in the UK that I can sit in the sump and array with LocLine manifold and pipes? Would benefit from your suggestions here. <I do believe the closed loop manifold with a single pump or two is best for the long term. Do read the thread of links stickied at the top of the All Things Salty forum at reefcentral.com. A couple dozen fab threads with pics> PS Good article on flow by the way (anemone owners take heed). Regards Jim <Thanks kindly my friend :) Anthony>

Closed Loop water circulation 3/16/05 I've been not able to see answer to a basic question about closed loop schedule. <do see the extensive list of links I have to this subject over in the "All Things Salty" forum at reefcentral.com. There is a sticky thread at the top of that forum... many posts with pics :)> My setup is a 180g reef + 75g sump. I setup a closed loop with two 1" intakes in the two overflow boxes to feed a Dolphin Ampmaster 3000. The return is made in 9 different locations in the tank. The tank has been running for 3 months and my soft corals and fish are doing fine so far. <ahh, good to hear> I run the closed loop continuously - no stop. Do you think it is a good idea or do I have to produce some kind of intermittence? thanks, Didier <random turbulence is very fine and arguably better. Leave it exactly as you have it. Wave timers are not needed. A waste of money IMO, although current switching devices (versus wave timers that shut off pumps intermittently) are novel. Anthony>

Sump and Closed Loop Manifold 3/2/05 Bob, I have read thru countless Q&A's on wetwebmedia.com, but still I can't figure out the best way to set up my new tank plumbing. Hopefully you can help. <Adam here today. Thanks for looking through the FAQ's first. I hope I can help!> I have a standard 75 gal rectangular aquarium and I want to set up the closed loop manifold system (No powerheads!). My glass has not been drilled yet, so we have flexibility here. My tank is going to be a reef tank with soft corals, fish, and inverts, but I would also like to design for some future flexibility if I decide to add more advanced corals later on. I need some guidelines for my system setup....Please help! 1) What GPH range do I need going through the sump? <If your sump is just a sump (no refugium or sand), then the range can be from zero to infinity. The limits are really determined by what your drains can handle.> 2) What GPH range do I need going through the closed loop manifold? <For reef tanks, I generally recommend at least 10x the tank volume, so at least 750gph.> 3) What bulkheads overflow sizes would you suggest for me? I was thinking (2)-1.5"s for the sump and (1)- 2" for the closed loop. Or, would (1) 2" bulkhead work for the sump? <The number and size of drains depends on the flow through your sump. A single 1.5" drain will handle about 750gph. For the closed loop, you want to make sure that you distribute the "suction" of the inlet widely enough not to suck up fishies! For a 750gph flow, a single 1.5" inlet with a large strainer should be sufficient.> 4) I still haven't found a site that tells me the max GPH for the range of bulkheads...can you help a little more with that? <We get that question so much, I may go make a WWM page! For drains, I would guess about 300,750,1000 gph for 1", 1.5" ,2" bulkheads. I would make a similar suggestion for closed loops as long as a large strainer is applied.> 5) How many outlets do you recommend for the closed loop? Is 3-4 enough? <At 1/2" each, that is probably too many unless you provide more flow. If you use too many, the flow will be too slow to be effective.> 6) What GPH range per closed loop manifold outlet do you generally shoot for? <This again depends on the size. For 1/2" outlets, I would try to get about 300gph each.> Thanks in advance for your help. -Cody <Best Regards! Adam>

Re: New 75G tank setup: Sump and Closed Loop Manifold <Don't know where Adam's gone off to, so am responding> Thank you for your quick answers to my setup questions. After reading through your answers, I now have a few more questions about the same setup (75Gal): My local reef guy can drill holes up to 1.5" bulkheads. So I plan to use 2 holes for the overflow (sump) and 1 hole for the closed loop manifold (all holes being 1.5" bulkheads). <Okay... the return does not have to be this big... just the size of the plumbing/fitting from the pump discharge... likely no more than 1" diameter> 1) If I do include a refugium in my sump, then what should my GPH (in the sump) be and why would it be different than not having a refugium? <Good question... how to state this... it's actually better to have the flow here "running in parallel" rather than series... that is, to have a much slower (a few, like a handful) turnovers per hour in the refugium itself> 2) If I try for 750 GPH through my closed loop manifold, and each one 1/2 inch outlet should have about 300GPH, then I am basically only going to have 2 outlets (returns) in my closed loop manifold (375 GPH per outlet)...is that correct? <Mmm, the math looks about right... but I would make more discharge points here> 3) If so, then would it just be better to split the flow with piping instead of plumbing a closed loop manifold? <If all you were hoping to do is discharge the water from two points, yes> 4) Assuming I have 750GPH in my sump and have 750GPH through my closed loop...both will be split into 2 returns each for a total of 4. Is 4 returns of 375GPH each enough to cause a sufficient turbulence in my 75G tank without the use of any power heads? (assuming I use modular piping and nozzles to accelerate the flow) <Yes> 5) Any other corrections / or comments about my suggested setup would be appreciated. 6) I have read in other Q&A's that you only want to run overflows at half their possible flow rate to cut down on noise. Is this true? <Mmm, practically speaking this is not a real concern... as you will find> 7) I assume since there will be no air introduced in a closed loop, I would probably be able to max out the flow through the bulkhead, and not use the "half" rule talked about in question #6...Is that correct? <Yes> 8) What are the best all-around pumps (brand) in your opinion that combine reasonable cost, low noise, and reliability? (please consider my proposed setup in pump selection) <Please read here: http://www.wetwebmedia.com/pumpselmar.htm and the linked files above... You will find there is some sort of consensus re manufacturers, the rationale for such... Bob Fenner>

Refugium, Sump, Closed Loop, and Overall Tank Flow With your generous help, I've been planning my new 75gal rectangular reef with a regular 31" tall stand; however, when considering adding a Caulerpa refugium, I have ran into a bit of a snag. My plan was as follows: To get 20x of overall flow without the use of powerheads. I planned to use (2) 1.5" bulkheads as drains for the sump and pump this 10x (750GPH) of return up over the top of the glass and into the system. A separate 1.5" bulkhead was going to be used as an inlet for a closed loop which also went over the top of the tank and in for another 10x (750GPH)---4 return nozzles total. (Bob agreed that this was a good setup). <Still do> But now I am considering putting a refugium in my sump and possibly grow Caulerpa. The max flow rate that you suggest for the sump/refugium is only 2-4x instead of 10x (that's a big loss in flow!) Bob also suggested that running the sump and refugium in parallel was a better way to go. <Is... or possibly adding another sump/refugium altogether> I was set on running an all in one refugium/sump like the picture shown in Get Thee To a Refugium, but if I do that, now I've lost 6-8x of flow which I must make up for somewhere else. It seems like I need 2 separate sumps one with a refugium and one without which means I need yet another pump I guess. <Possibly... or a plumbing manifold... with valving... and one pump> The problem is that I don't have room in my stand for two of them to run in parallel nor have I found any sump designs that show parallel flow like you suggest. <Could one (sump) be run above the main tank? Outside of the stand area period? Doesn't need to be just put under...> 1) What are my options to have a single sump/refugium but not limit my flow down to 2-4x? 2) Are there any links that would help me design such a parallel flow system in such a limited space? <Maybe Ozreef.org...> 3) I guess if I was only running 2-4x through my sump/refugium, I would only need (1) of the 1.5" bulkhead drains (running half max flow) and I could use the other (2) 1.5" bulkheads to feed 2 closed loops? <Could... but one loop would be fine...> 4) Is there anything wrong about running a sump refugium at 10x ? Thanks in advance. -Cody <The contents might well get swirled about like being in a Maytag! Bob Fenner> other dialogue provided below for reference <Thank you for this.>

Re: Refugium, Sump, Closed Loop, and Overall Tank Flow Bob, Can you explain this further? I'm not sure I understood what you meant. A plumbing manifold in the sump? What does this look like? <Possibly... or a plumbing manifold... with valving... and one pump> <<Like a "gang valve" for air distribution... you can "tee" off the discharge from the one pump... and use two valves to regulate water flow>> And by the way, I cannot put a refugium on top of my tank.. Everything has to be within the cabinet below. <<Okay. BobF>>

Closed loop manifold I have a pump that runs 1900 gallons @ zero head and shuts off at 45. This pump will be in the basement and will have about 20 feet of head by the time it goes through the manifold at the top of the tank. Champion lighting said I will still have about 1200 gallons per hour. I am running another closed loop pump same size as the sump to a manifold at the top of the tank as well. My question is do I need to run 2 separate manifolds or can I hook both pumps to the same manifold and save some clutter at the top of the tank? <You can do this providing the plumbing is sufficient enough to handle the volume of water. Personally, I don't like hooking up two pumps to one outlet. I think it lowers the efficiency of system. James (Salty Dog)> Thank you. <You're welcome>

- Plumbing a Return Manifold - Hello and thank you for all previous advice. I am in the process of creating a return manifold like the one Mr. Calfo has posted. I am planning on using a Blueline 200 with 1" inlet/outlet. I plan on using 8 T's in the manifold and use adapters with swivel nozzles to finesse circulation. Question 1: Since pump outlet is 1" should the whole manifold be constructed with 1" pvc? <I'd plumb up to the tank in 1"... for the manifold perimeter around the tank, I'd use 3/4".> Question 2: I would rather support manifold above water line/above tank center brace and extend T's and nozzles below water surface for aesthetic reasons. Any issues with that? <Not that I can think of, provided you put a check valve in the main return line, before the manifold.> Question 3: I don't want to drill the tank but would rather plumb inlet from display-over rim-down to pump. Problem? <A huge one... would create a siphon.> If not, as I understand it, or maybe not, in case of power failure, since this a closed loop (no sump) method there is no chance of flooding, correct? <Didn't realize this was a closed loop, but still must make an allowance for a leak in the plumbing/pump. Siphons are big potential trouble.> Question 4: Scenario--> power fails resulting in inlet plumbing over display rim drains back to display creating a air gap but there is still water in vertical pipe above pump. Will this be enough water to prime the pump when the power should happen to come on again or will I burn up the pump trying possibly creating a fire and burning the whole house down b/c I didn't want to drill the tank??? Duh <Hmm... good question and something I would test once you have the whole thing built. Do think that if you use the check valve inline on the return, you should have enough water remaining in the plumbing to prime the pump. Again, would test this to be sure.> Thank you for guidance and patience. Avid reader <Cheers, J -- > Closed loop system Hello, I have a few questions regarding a 46g bowfront I'm in the process of setting up. I don't have room for a sump, so I'm planning on using a hang on skimmer and an external pump set up in a closed loop system. << Good ideas. >> I'm considering drilling the back of the tank for drain and return lines to minimize equipment going over the back. << Great idea. >> For the return, I thing I'm going to use two 3/4" lines coming from a SCWD. My question is about the drain. What would you recommend for the bulkhead size. << One and a half inch. >> I'm thinking that about 600gph(at 4 feet) should be about right for this size tank. Any pump recommendations for this setup would be greatly appreciated as well. << More important is to make sure you use ball valves and unions, you will have to take the pump out for cleaning, so plan ahead. >> As always, cost is a factor. Thanks so much for the great site. << Blundell >>

Plumbing, marine, closed loop Hi Guys....wonderful site. Many thanks >>Thanks back!<< A quick question if I may? I have a 75g display, 30 g sump/refugium. Plumbing is a 1" bulkhead (I.D.) drilled at the back in the tank with a flexible hose going into the sump with a mag Drive 9.5 forcing the water back up over the rim of the tank into a single elbow/effluent. A lot of flow/velocity...too much laminar I'm afraid. But So far....the balancing act is perfect. Water level in sump matches the pumps output pretty nicely as there is no need to use the ball valve to divert flow. (this seems to defy the 600 gph flow rate I read about with a 1" bulkhead) I have been reading Anthony's suggestion about making a return manifold to more evenly disperse the water throughout the tank. Probably will give that a go this weekend. >>Great. Such a manifold works out very nicely.<< Also, I have 2 small Rio's in the tank for additional flow,(240 gph each) along with a Euroreef CS-6 skimmer in the sump stirring things up even further. Will this be adequate flowage for my setup? I do not have any livestock in the tank yet...just 130 lbs of Fiji rock. After scouring your site...I've seen that 20x tank volume is pretty much the norm these days. I do want a few fish...but mainly corals and inverts. >>You don't really need 20x moving through the sump. More flow in the main tank is nice though. >>The Rio's make me a little nervous though, they have a rep for burning/shorting out<>If you want more flow, sure! Sadly, the amount of flow in a tank is partly a function of the corals you keep and personal preference. I know on my tank, I never seem to have enough flow regardless of all the extra closed loops I add!<< I do not want to drill additional holes for plumbing, so I was thinking about looping pvc from the top of the display tank, gravity feeding into another mag-drive of some sort, (size recommendation would be helpful) then shoot right back up into the display (no even going into the sump...just independent) maybe splitting the effluent into 2 feeds? ("T") this way...could I eliminate the Rio's inside the tank? >>Sounds good to me. I like removing any kind of power head from the tank, and I run my closed loops over the top instead of drilling - I think it give greater flexibility for the future. You can also look into a device called a SCWD that is basically a 'T' that alternates the current between both sides of the 'T' by a series of gears powered by the water flow. There are, or course, more expensive options like the oceans motions 'Squirt' - I just got one to replace two SCWD's and I love it so far! As for pump size, that depends on how much flow you want. Mag 9.5's seem to be a good all around size. << Thanks so much for the insight... >>Hope it helps!<< Mike Gaydos >>Rich<< Re: Plumbing, marine, closed loop Hi Rich, Thanks again for taking the time to respond to me. All this information is surely a lot to digest for a newbie like myself, but I keep reading and learning. Anyway, I guess my main misunderstanding about flow rates comes into play when the term "turnover" is used. I thought 20x tank volume meant all water must go thru the sump. So then what you are telling me is not all of that 20x must go thru the sump but rather just get "moved around" by a combination of sump, skimmer, powerheads in display, and closed loops?? >>That is exactly what I am telling you! Its important that there is 'enough' flow around the corals, not that all the water must pass through the sump>> Could you please tell me what the desirable amount of water MUST move thru the sump/skimmer to be effective at filtration and the rest just for water movement? >>I can give you a sideways answer - as much as possible. In my case, 600 gph moving thru overflow/ return, 350 gph thru skimmer, and possibly another 600 gph moving thru a closed loop over the top of the tank be adequate? Sure seems like a lot to me.... >>The skimmer doesn't count as flow or turnover unless it is a HOB skimmer. The animals in the tank could take more flow, but you don't have to add more unless they need it. Does it move around the tank briskly? Are there no dead spots? Then you are fine! >> One other question please about closed loops. How do you prime the pump if it is fed by the line hung over the top of the tank? >>The easy way is to fill the line of the loop with water before you hang it over the top of the tank. You can also plumb in an ball valve above the tank so you can open it and fill the line with water. That makes sense, really>> I'm sure the supply must at least originate roughly in the middle of the tank with some sort of filter/screen over it as not to suck in anything undesirable? >>Screen yes. You can put the intake where ever you like in the tank (I hide mine behind the rockwork) or if your overflow will take the extra flow, you can stick it in the overflow.>> Once it is primed...it should continue on until power is disrupted or would it continue to siphon? >>Yep! (ok...that was 2 questions) >>3!>> Oh....one more....please......where does one drill the anti-siphon hole in the manifold as described by Anthony? Cant have it above the water or it will spray while running....so in the "loop" somewhere pointed downward or is it even necessary at all? >>Some people don't use them, but they are a good idea. If the power goes out, the manifold will continue to siphon your tank. The anti siphon hole does go slightly above the water line, drilled in such a way as to point slightly downwards so its 'spray' doesn't hurt anything.>> Thanks so much....really! Sincerely Mike Gaydos (rookie) >>My pleasure!>>

Re: closed loop Can I take squeeze in another closed loop question? I'm pretty clear on flow rate now...thanks to you. Could a person who only has the lone 1" overflow bulkhead installed (with limited 600 gph capacity) plumb in a closed loop hung over the top of the tank.....gravity fed into a pump, but them have the effluent merge into the manifold to increase volume that way? The manifold will be 3/4 with at least 6 elbows/returns. Should have plenty on room in there for the extra flow provided by the closed loop?!? This make sense? >>Makes sense but is generally considered a bad idea because it makes the pumps 'compete', or push against each other>> One last thing.....Will the Kansas City Chiefs be able to make the playoffs with the rather rocky 1-3 start this season? >>Sadly, no>> And if you could supply me with the winning Powerball lottery numbers that would be cool too... Thanks a bunch. >>7 3 8 9 5 33>> Mike >>My pleasure>> >>Rich>>

CLOSED CIRCULATION LOOP WWM Crew <Hi David, MacL here with you this evening.> I'm planning/preparing to convert my 37g reef to a sump and closed circulation manifold, and was hoping to get your input/critique on my planned setup. The sump is going to be constructed of a standard 10g aquarium - it's cheap, and it's the widest aquarium that will fit under my stand; it will also allow me to continue to use my CPR BakPak (I don't think it will hang on the side of a Rubbermaid/similar container). I'd planned on dividing it into 3 chambers (very simple setup), for skimmer, return pump, and a larger center chamber that will eventually house some macro algae (probably Chaeto). I'll be using a CPR CS series overflow, rated for 600GPH. I've already made sure (in theory anyway) the sump will have more than sufficient volume to house the overflow water when the power goes out... I'm shooting for ~500gph water movement, and I plan to plumb the return and make the manifold from 3/4" PVC. I'd originally planned to use a Mag 7, but after experimenting with an online head loss calculator, with the configuration I roughed out the 7 is only going to make ~340-350GPH... Do you foresee any problem with moving up to a Mag 9.5 and staying with the 3/4" PVC? According to the same calculator, that should get me 490-500GPH (got to get rid of those powerheads!!). I don't want to spend the money on an Iwaki right now, and I prefer to stay away from the Rios... While I've got you, does Chaeto/similar require a substrate or anchoring substance, or will it grow ok floating freely? I hadn't planned on putting any sand in the center chamber, but could put some live sand and/or LR frags if the macro needs it to take root... Thanks in advance... to be able to tap into such a tremendous and well-respected pool of knowledge is invaluable to us who are still learning... David

Closed Loop Options Hello, <Hi there, Scott F. your Crew Member tonight> I've been reading all of your FAQs on circulation. One question I have is concerning closed loop circulation. I have a glass aquarium and so cannot drill bulkheads. What is the best way to set up a closed loop circulation. It is a 50 gallon tank, which currently has a mag 7 pumping 500 gal/hr from the sump and another pump that is pumping around 300 gal/hr from the sump. I want to add an Eheim 1262 which pumps about 900 gal/hr but don't want to have to pump it with a 4 ft head nor deal with all the extra water going into the sump. Additionally, with the 4ft head the pump looses 200 gal/hr. Do you have any recommendations for the intake pipe and how it should be configured? Thanks, Brent <Well, Brent, if it were me- I'd keep it simple and not do a closed loop at all. I'd opt for top-mounted external pumps, such as Tunze Turbelles or Aquarium Product Geminis. The put our massive flow (up to 1,000+ gph), impart virtually no heat to the aquarium, and use miniscule amounts of electricity (as little as 15-20 watts!). And, best of all- they require no drilling or supplemental plumbing connections! If you can handle the aesthetics (and cost!), internal Tunze Stream powerheads are the way to go. The simply move huge amounts of water with great flow, are controllable, and are of the highest quality! Check these ideas out! Good luck! Regards, Scott F.> Plumbing Manifold 8/12/04 Hi Crew, <howdy> My name is Keith. I have a couple of questions concerning Anthony's plumbing manifold. A little history first. My system will be a 125g main tank, 15g sump and 30g refugium. The tank is up and running (sort of). I got into a salt tank with too little knowledge and have had some problems. Copper in my water and poor water flow were the two main problems. I <the latter is a very (!) common mistake. The minimum should be 10-20 X turnover per hour. You will likely need 2000-300GPH turnover here> I have corrected the copper issue. I have to take my tank down, get rid of the substrate and (at one time) live rock. Currently the only overflow is a HOB with one 1" U tube. (LFS said was plenty - yea right) I have found some one local to drill my tank for me. <excellent! A drilled overflow is the best/safest> Now for the questions. 1) Do you recommend drilling the bottom of the tank or the back for overflows?. <always the back... I still cannot fathom why some folks recommend drilling the bottom. It is harder to plumb around, requires an awkward/large standpipe or overflow tower... and is simply an unnecessary risk. The high vertical (back usually) walls are best, safest and most discreet> 2) Will two 1.5" overflows be large enough?. <not sure... is this the bulkhead size or the drilled hole size? If the former, that would mean your drilled hole is around 2.5". Moreover... simply determine how much flow you want (2000-3000PGH) and compare against the bulkhead mfg.s specs (like at Rainbow Lifeguard plastic website). This is the only way to safely rate it> 3) This is the main question(s) - if I use Anthony's design for a manifold does the return need to come from the bottom or back of the tank?. <the manifold is to be fed by the sump return pump likely. Else an in tank pump> Once I get the return to the top of the tank, will the manifold be above the overflow box's or do have to use elbows to go around both box's?. <whatever is practical... I cannot say as I do not know where the overflows are placed. The manifold typically sits just at or slightly above the water surface to be discreet> The last and final question has to do with balancing the flow from the nozzle's. I will be using a T4 Velocity pump rated at 1250gph with 1" intake and output lines. <this is very little flow/pump for a manifold. Just imagine if you have six nozzles fed by this pump working at head... that's less than 200GPH per nozzle (weaker than the smaller powerheads). A dismal water flow. Beef this up, mate> I was planning on having ten nozzle's in the manifold, 4 in front and back and 1 on each end. <ten nozzles sounds excellent for the tank to improve water flow and reduce detritus, etc> Will I be able to get enough flow through this manifold that the front nozzle's have a good flow of water?. <not enough> Thank you for your time and all the good information I have gotten from reading for hours on your web site. Keith

Goodbye power heads (re post) 2/27/04 Hi Anthony or other helpful crew member, <whassup?> Some time ago I wrote you about setting up a "goodbye power head" system. I have a standard 75 gal non drilled reef on a regular stand. I was going to use a over the back siphon as input to the pump and then run it back up as in your design. <yeeeeeikkes. Siphon overflows are no part of any system I would/did/will ever recommend. They are patently risky in the long term at best. DO reconsider. If you cannot drill the tank, I'd rather see you go sumpless than use a siphon overflow> I am ready to "make it so" but have a few more questions. 1) On the intake, should I plumb it like a external Durso with a cap on the pvc so the pump can be primed? I am thinking it will always stay primed even if the power goes out or am I missing something? <missing much my friend... there are many things that can and will break this siphon over time: accumulated microbubbles from sump pump, skimmer effluent, O2 production off corals and plants by day, etc)> 2) Should I use a pressure rated pump or a volume? <not sure here without knowing/seeing the plumbing. Still I suspect it will not be that complex and as such either pump will work. I'd opt for pressure rated> 3) Would 1/2" pipe for the return be ok? as 3/4 just stands out around the tank to much. <Likely fine here... will require some experimentation> 4) What GPH would you recommend at around 4' head and 4 90 elbows. I was thinking around 800gph or so. <too low here my friend... opt for 20X for better results (10-20X is minimum and some of the best tanks have near 40X diffused). Find a pump that delivers 1500-2000 gph at the head you will apply>> Can you recommend a brand or model? I have shallow pockets! <good things are seldom cheap and cheap things are seldom good, bud. For how large this overall investment is (many thousands of dollars through the first few years)... saving $50-100 on a cheaper pump is not worth it. Buy quality made to last like Iwaki and enjoy is 3-5X longer than the cheap pumps. Opt for Japanese made Iwaki (better built)> Thanks to all the crew for the great service you provide to all of us! <thanks kindly, Anthony>

Aquafuge pro and closed loop circulation 3/2/04 Adam, No doubt about it I'm going closed loop for circulation. The biggest concern I have right now is drilling the back of a brand new tank for the intake to the pump. You know the feeling you get when something is brand new and you think you'd like to tinker w/ it but you need a push in the right direction? What I'm looking for here is a vote of confidence. <This is definitely a scary thing! If you do decide to drill, I would seek the advice of the tank builder and/or someone local who has experience. Aside from the risk of damaging the tank during the operation, you must be conscious of not weakening the structure of the tank and risking future failure.> My plan is to place a bulkhead w/ strainer about 8-10" from the bottom on the back panel for intake. <The lower you place the hole, the more water you can potentially lose if it ever leaks. Consider placing the hole higher and using plumbing to get your intake where you want it. It can be hidden in aquascaping. Do also consider simply plumbing the intake plumbing up and over the lip of the tank and into position (no drilling required). Now, reading about all the pumps out there and their different intake sizes leads me to another question: what size opening should I drill for 1400 gph flow? I have eliminated 3/4" so far, also eliminated the SCWD in the line because of it's 3/4" input/outputs (just murdered my flow rate). What I will end up w/ is a 1" manifold 4-5 outputs. Should I select pump first and then match input size? Marine tanks are not new to me, every aspect of plumbing is. <1" bulkheads should be adequate for 1400gph, and will match most pumps in this flow range. Purchase and measure your bulkheads to determine the required hole size. There is often some size difference between brands. Even if the pump has 3/4" outlet (Little Giant may), I would use all 1" plumbing for max flow.> Thanks, Sam <Best Regards. Adam> - Plumbing a Closed Loop - Hi - My question (today) is about plumbing a closed loop system. I looked through the FAQ, but didn't really find anything to address this question. I have a 180 gal acrylic tank that is 60" long, 30" side and 24" tall. It has two overflow chambers on each end, 8" square each. There is a "coast to coast" overflow 4" square across the whole back of the tank that flows into the overflow chambers. I drilled holes for bulkheads for a 1" Durso standpipe for outflow to the sump in each of the overflow chambers and a 3/4" return that is piped through the overflow chamber and into the tank itself. Although I drilled each overflow for a return, I'm finding that one 3/4" return from my Iwaki 40RLT pump is sufficient. The second overflow is turned off at the ball valve. I had wanted to use an 1 1/4" outflow, but found that I could not get elbow of the standpipe into the chamber. The 1" seem to work fine, so that's not an issue. Now for the question - I have a Dolphin 3600 AmpMaster pump and a Haywood Electrical Ball Valve to create a closed loop system that will change flow as the ball valve swivels from right to left sides. <Hmm... just a word of caution here. Do observe carefully your pump's interaction with the ball-valve - my feeling is that the switching between the two outlets will cause back pressure on the pump.> Both the pump and the ball valve have 1 1/2" input and returns. I have room in the overflow chambers for one more 1" bulkhead that I can to tie together and with a 1 1/2" tee underneath the tank. But I'm concerned that I'll be pulling too much water through the overflow chambers and unless I get the standpipes exactly the same height, I'll "starve" either the closed loop system or water flowing into the sump. <Possibly - if you haven't already, I'd go through a wet-run/leak test - just fill the tank with fresh water to make sure all works according to plan.> The other method is to pull the input for the closed loop from just below the 4" square coast to coast. <Perhaps a better idea, although plumbing failure will cause a good deal of water to drain out - how about a bulkhead in the coast-to-coast?> The return from the Dolphin will go to 10 - 1/2" Loc Lines. I'm also not sure whether it's better to drill two 1 1/2" bulkheads in the back of the tank for the returns and have 1 1/2" to 1/2" tees inside the tank or to have the 1 1/2" to 1/2" tees outside the tank and drill for 10 1/2" bulkheads in the back of the tank (I'd also do this as close to the coast to coast as possible - just in case one leaks I want to try to minimize water loss). <More holes will weaken the tank - I'd go with as few holes as possible.> By having the 10 holes in the back of the tank, I'm taking up less tank real estate by not having a lot of visible plumbing along the back of the tank. I'm not too concerned about drilling ten holes - I've gotten fairly good at drilling acrylic :-). Thanks in advance for the answer. Steve
<Cheers, J -- >

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