Possible Megaflow solution?? Plumbing questions?? 12/22/08 Hey guys, Thanks for the great site! <Thanks for visiting, hello!> Here's my current dilemma. I just attempted to install a "Glass-Holes overflow kit" on my 72 bow. They offer a 2x1.5" overflow box that runs 1500gph. The issue here, is that the overflows are predrilled in the rear of the box at aprox 3" apart. I bet you can guess the next part.?? <Hmmm, no.> Well, I assumed that this sounds logical and worked well in the video on their site. <And for 1000's of installs around the world.> So I started drilling as per the attached template and instruction, hole one-ok,...hole two-looked ok. After I wiped away the milky film, I saw a nice thick hair line crack between the 2 holes. After discussing this with a glass company, they said to stay 8" apart min. on holes. <Based on what? This is quite an arbitrary, ridiculous number. Many factors are involved: glass thickness, hole size, height of the tank, and placement within. The tried and true industry standard is one hole width apart. Take a look at the Oceanic Tech series, many holes drilled mere inches apart.> Ahh... Hindsight!! <Really just the risk one takes anytime drilling glass. I do own a stake in the Glass-Holes.com company, do contact us re a refund of your purchase if you wish, we do stand behind what we do!> So I now have a 72 bow turtle/reptile tank. OK, now that, that's done, the reason I am writing is I am now looking at a new 90 gallon reef ready tank setup. This new 90 gal RR tank will feed a 30 gallon sump with a 300micron sock, a ASM G2, 2 sets of baffles and a return compartment for internal pump and heater. I may also hang a HOB CPR 19"x4"x12" fuge on the sump as well. I will be keeping softies, LPS, and possibly SPS once I get MH lighting. I can't afford big $$ on a custom tank, and it seems the only option that I have found in the Chicagoland area is the terrific "Megaflow"...... <As you imply, not so "Mega".> So, I started thinking on how to make the Megaflow, flow better. What is your thought's on this. Using both the 1" drain and the 3/4" return for drains to the sump. <Honestly common practice with these. Do note that these holes here too are drilled within 8" of each other.> Then as a return line, I want to use a 3/4" SCWD, and just feed back into the tank with 2- over the rim returns/modular fittings--one on each corner. <A fine way to route returns.> So could I assume that total drain to the 30 gal sump is 1- 3/4"(aprox. 300gph) and 1- 1" drain(aprox. 600gph)=total drain to sump approx 900 gallons(this of course does not include any 90's or restrictions)? Is this at all close? If it is not correct, what would you say the flow would be? <Not really. A 1" will only flow 300 gph safely, with a ¾" about 160 gph.> What mag pump would you recommend to return via a 1" flex into a 3/4" SCWD, then out to the corners and over into the tank? <A Mag 5, maybe 7 with a ball valve to control the amount of flow. Neither leaves you with any overflow redundancy.> Does this idea of using the additional 3/4" drain sound like it's worth the time and effort? <It is worth it with these things.> Is there a better way? <Drill it, even if just one 1.5" drain through the back, within the Megaflow box.> What is the best way to plumb the 2 feeds? 2 Dursos? <In this scenario yes.> Is there any way to get better flow from the "MegaFlows"? <A new product we/GH are currently working on, not quite there yet.> Should I stay away from the MegaFlows? <I in all honestly would.> Any better, economical options? <The one you bought IMO, just a bad turn here. Like I say, it can and does happen sometimes whilst drilling glass, or drilling wood/anything for that matter.> So my other thought to gain some flow in the new 90 gallon megareef tank, besides a single Koralia 3, is to drop a pump into the rather large Megaflow overflow chamber and use the factory Megaflow modular return as an internal closed loop(since I am using the 3/4" return as a drain) . Any thought on this? <This can work so long as the intake and output of this pump are drilled through the overflow box. Otherwise it will affect the amount of water in the box, creating many other issues.> What MAG pump would you recommend to use in this Megaflow cavity for return? <Would not, a traditional closed loop or powerheads are a far better way to go.> Is there a better pump for less heat then the MAG? <Eheims, Oceanrunners, among many others.> Also, what do you think of this setup as a whole(drains--1-3/4", 1-1"------return possible mag 7.5 or 9.5 thru SQWD into 2 returns-----small pump in the Megaflow cavity thru factory return-----Koralia 3 across top of rocks? <See above.> Does this sound like enough flow for SPS's? Should I use another Koralia 3, one on each end? <I would for SPS here.> What is ideal flow, although-not direct flow, 15x-ph, 20x-ph? <On the higher end here.> Why can't AGA see the need for bigger drain? <A question I have asked for years.> Thanks for all your time and thoughts on this. Randy-Chicagoland <Welcome, best of luck, Scott V.> Re: Possible Megaflow solution?? Plumbing questions?? B-feel free to post PDF  12/24/08 Hey Scott, Thanks for the info and the timely response. <Hello again Randy, happy to assist.> I have been in the fish hobby for 18 years(13 fresh, 5 salt), and I find the info from this site is 2nd to none. <Thank you!> It has been a constant, reliable resource for anything fish related. I send thanks to you and all of your partners for this! <Will be seen/passed along!> I do have a few other questions if you don't mind. Also, by no means was I bashing GlassHoles.com, I found their product/overflow box to be of excellent craftsmanship. It's a cool setup and a way to get the surface skimming without losing lots of space. <Ah, no worries. Not perceived as a bash, just want to help you and others out where I, we can. I do apologize if my response seemed defensive.> It's just a bummer that I drew the short straw this time when drilling! <Tis the case, it does happen, but stinks.> I have thought about trying another tank and putting the overflows on each corner but knowing my luck I may have the same results.?? <Consider visiting a glass co and acquiring some scrap to practice on, you can easily get 20 holes or so out of the bits.> So, as my plans are still pretty liquid in structure regarding the new tank setup, I am now narrowing my choices down based on drain size and flow. With this said and after reading both good and bad reviews about Glasscages.com, I am looking either their 90gal(48x18x25) or a oddball-125Tall(60x18x25). <I have dealt with many customers using their tanks. The general consensus I have heard from them is good for the money; perfectly functional.> Most likely it will be the 90(based on wall location and size). Glass cages will drill what ever I want, wherever I want(I know this is a little possible with AGA and Oceanic, but seams to be more difficult based on, LFS, dist, Aqueon's involvement). <They will, but dealing directly with the builder does have advantages.> BTW, to refresh, My setup-- 90gal will have 1 overflow in the rear center(overflow and drain size/qty to be determined), it will feed a 30 gal sump(currently setup for 2-1.5" intakes) into a 300mic sock, ASM G2, 2 sets of baffles, then return pump in final compartment. I may add a 18x4x12 CPR HOB fuge onto the sump. Return will have a 3/4 or 1" SCWD and either thru tank(high) or over the top modular returns. Tank will have 1 or possibly 2- Koralia 3's. So here are my questions: -My overflow box will be drains only and will not be used for any returns. If you had a perfect world to live in, and were asking for the ideal flow for the 90 w/center rear overflow, what would you want with my 30gal sump? 2-1.5"?, 3-1.5"?, 2-2"? 3-2"?? <Dual 1.5� or 2� will do the trick. You do want to have a 100% redundancy in case of a drain plugging/failure. Taking this into consideration the dual 1.5� will allow you 750 gph, while the dual 2� will give you 1300 gph, both of these scenarios offer 100% redundancy.> I am going to try and design this as best as possible for SPS's, but it will be in the family room and noise needs to be as low as possible. -How far apart do the drains need to be for Durso clearance? <Not too far, the width of a PVC elbow.> Do you know how wide the top of a 1.5" Durso is? <Whatever the width of the elbow/fitting is, 2� or so.> -I think Glass cages std. overflow is a 6"x10". <Plenty of room.> For the above "ideal" drain info , ideal drain number and sizes, what is the perfect overflow box size? <A loaded question for me! The 6X10 is fine.> I know it's based on linear flow? <Not really, more a matter of bulkhead size. Linear overflow length is highly overrated in the forums nowadays.> Not sure how noise and suction plays into it? <Suction should not play into it at all with these appropriately sized drains. Noise is a function of the amount of water flowing and the Durso you will use.> -What do you think this will put my GPH thru the sump at? What's ideal sump GPH? <Flow does depend on the pump ultimately. Ideal IMO is 600-900 for manageability here.> -Should I run a Y and 2 sea swirls instead of the SCWD? <You could, this is all about implementing the flow you have, see here: http://www.wetwebmedia.com/circmarart.htm > -On my return, based on the above drain number and size, which MAG pump do you recommend for the SCWD? <A Mag 9.5> -Which SCWD(3/4" or 1") do you recommend based on above drain number, size and return pump? <A ¾" for one return, dual ½" for two.> -My returns, is there any advantage/disadvantage to going thru the tank or going over the rim? <The big disadvantage with drilling these is siphoning into your sump when the return pump is off; this will happen with over the top returns also, just usually to a lesser degree. The advantage is merely aesthetic to some.> Where is ideal placement if I go thru the glass? < If you do drill you will want to do so as high as possible, making sure your sump will have the capacity to handle all the water that will end up there in a power outage.> -With the sump return and the 2 Koralia 3's, is there any need for a closed loop? Location?? <Hmmm, no need with the 3�s. Powerheads are the way to go IMO. Just so much benefit re adjustability and power consumption.> -Will the 18x4x12 CPR HOB fuge(on sump) do me any noticeable good or is it to small to do any good for the 90gal? <Bigger is better, but something is better than nothing. You do not have room to divide off a section in the sump?> -Any thoughts on Glasscages.com? <Stated above.> -And last, I have always used MAG pumps, what do you recommend in it's place that is more efficient and less heat without breaking the bank? <First choice is Eheim, cheaper second is the Oceanrunner series.> Thanks again for all the time dedication to this awesome site. Randy <Thank you. I do urge you to either contact us at Glass-Holes.com re a refund if you do not intend to use the box or have the tank drilled by Glasscages for the G-H box (I have attached a PDF for hole location you can send them if you do go this route). This is too much to spend and not use or get reimbursement! Best, Scott V.>

Improved filtration/Overflow, sump setup 11/24/08
I recently set up a new 135 gal Oceanic reef tank. I converted my old 55ga tank into a refugium underneath. The refugium is a simple design. It consists of three compartments, divided by two acrylic sheets. The first compartment is where I keep my skimmer and heaters, this spills into my second compartment, which contains some live rock rubble and Chaeto algae, and then the final compartment simply contains my two return pumps. The volume of the system is approximately 40 gallons. My question is do you think this simple design will be very effective?
<Yes, tis the setup nowadays.>
Could I improve on it by putting a small pump (200 gph or so) in the final compartment and pump the water that was going to go to the display back to the first compartment to run through the process again so to speak?
<No, you want the raw water from the tank running to the skimmer.>
Also, I'm not sure what my two overflows are rated at (if that means anything).
<Typically 1� bulkheads, good for a bit more than 300 gph per, though �rated� much higher.>
My return pumps are rated at 740 gph ea (again ratings don't seem to mean much).
<Nope.>
The water level draining at the teeth on the overflows is not even half way up the teeth.
<Not a factor, the bulkhead is the limiting factor here.>
Last question, can it handle more return?
<Likely not.>
Is looking at the water level on the teeth a half-way accurate way to judge this?
<No, see above.>
Thank you
Corey
<Welcome, Scott V.>

Re: Revised Tank Plan (Last one)
Revised Tank Plan 9/1/08
Crew,
<Blake>
The planning of tanks can be very detrimental to all those around the planner, it makes for such entertaining day dreaming/"spacing out"! If only we put as much planning into work, relationships, etc...
<Exactly, could you imagine?>
The thought process on the Dolphin was that I could throttle it back using a gate valve without harming the pump. I was considering having aprox. 1000-1200gph through the sump.
<You could do this, I would just choose a smaller, cheaper to buy and operate pump.>
Are 2 in. drains necessary?
<Even with this flow they will be if you want two drains with either one being able to handle the entire flow. A 1.5” drain is only reliable for 750 gph or so.>
The Herbie method of overflow only uses one of the throughputs and the other is strictly a safety measure.
<Ah yes, I am familiar with the method, not the name. I apologize for not catching this in your previous email. While many use this method with some success, it is still not a good idea in my book. Taking an overflow and restricting it to balance the flow will always fail in time. I understand that is what the second drain is for, but consider the real danger: By using this method a siphon is created in the line that drains the water (many would argue there is not, but that is a whole issue in itself). By siphoning a 1.5” line can handle 1200 gph+. The issue comes in when this line fails. The remaining drain is now either expected to drain this flow gravity fed (and it won’t) or counted upon to create a siphon of it’s own. This just too risky for the floor/walls in my house! >
I travel a lot and want as many safety checks as possible. Can you recommend a pump that may be more appropriate?
<I personally like and use the larger Eheims in such applications, there are other great pumps out there: Iwaki, PanWorld, even a small Reeflo just to name a few.>
After reading Anthony's book "Book of Coral Propagation"(great read by the way), I've decided to use my old Coralife 220 skimmer and also upgrade to a MSX 200 (he recommended having 2 types of skimmers). Additionally, I am trying to plan plumbing a 5 gal. bucket of sand for a deep sand bed underneath the main display(unlit) and only using a 1/2 in to 1 sand bed for the main display. <Sounds like it will be a great setup.>
And oh yes, I love the idea about shaded areas and the aesthetic possibilities. Hopefully, I can find home for some softies and different types of bio topes in the same tank.
<A matter of researching re compatibility.>
Again, thanks for the time and help.
Thanks,
Blake
<Welcome, Scott V.>

Tank Overflow Design 9/1/08
G'day WWM Crew,
<Ben>
I have a 1500 litre 15mm thick glass tank (currently empty, upgrading from my 46 gallon) with no overflows and thought I already knew what I was going to do for overflows. I have an Iwaki MD20RX pump that will return about 3000 litres to the display tank. I will be using 2 x Tunze 6301 pumps for circulation, so the Iwaki is purely to return water to the display tank and supply my OctopusTDNW-300-6530 Recirculating Protein Skimmer via the overflow with about twice the tanks volume every hour, which should be perfect. My idea was to have 2 vertical corner boxes each with a 1" drain with possibly 1 extra 1" drain just for insurance.
I thought I would read a few Q&A's on WWM to see if this is the best way to go, and haven't read anything too positive on this set up, most articles I have read are suggesting a box mounted top centre running lengthways, but I can't find anything reliable on the net as to how best to build this type of set up.
<There is nothing wrong with the vertical boxes. Most the dissention you have read about is due to the throughput size that these types of boxes are usually sold with, they are simply too small. Your tank would fall into this category with dual 1” drains, it will be dangerously close to the capacity of these. Having the backup will be helpful, but if you are starting from scratch you might as well go larger, 1.5”. Another consideration re the overflow type is the fact that many tanks use tempered glass on the bottom pane (cannot be safely drilled). You will need to check with the manufacturer to see about yours, if it is tempered, a through the back overflow will be your choice.>
Would it be best to make an internal box from glass or acrylic, with 3 or 4 1" bulkheads, if so what would be the best way to attach this to the tank? I've read that there isn't really a good way of bonding acrylic to glass, so would I be better off making something from glass?
<You could use glass if you wish, nothing wrong with that. You can easily use acrylic, building a back panel on the box. Then you can drill the box to match the throughputs in the glass and use the bulkheads to hold the box in. Just pay attention to where your gaskets go! I highly encourage you to try the acrylic route if you are at all handy with DIY projects. It will make the box removable and once you learn to work with acrylic you will open up a whole world of DIY equipment options for yourself.>
What do you suppose the Ideal length for such a box would be? (I have an 8 foot tank).
<Up to the whole length of the tank if you wish! Really, a foot or two is more than plenty, there is a greatly diminished return re surface skimming after this length with this amount of flow.>
I hope you might have some suggestions or be able to point me in the right direction.
Thanks again for your help as always,
Ben
Adelaide, Australia
<Welcome, have fun with this project! Scott V. in Monterey, Ca today.>

Sump/Overflows 8/29/08
Hello again Guys, thank you so much for all the information you have given thus far. I have learned a lot from reading the FAQs as well. I have some thoughts and would like your opinions. I've decided to build my own sump out of a 15g glass tank; this is the only size that will fit in my stand. I read the info about the use of foam rubber to seal the baffles in place and will try that.
<It is a good way to start out, you can adjust if needed.>
In your previous response you said to use two 1.5" drains, looking at the Glass-Holes.com site I saw the one rated at 1500GPH. I assume this is the one you were referring to correct?
<It qualifies as one. Any 1.5” drain can work, even without a box. It just depends on what you want to see in your tank. Do a quick Google search on overflows, you will find a few to choose from.>
It seems to me like overkill for a 46g display tank, which will give it a turnover rate of about 32x per hour. Then again the more turnover the better right?
<More flow is good within reason. You do not want to run ANY overflow to the limit. Ideally an overflow will be run to 50% or less of its capacity, with multiple drains. Overflows can plug, having redundancy in place keeps the water where it belongs.>
Here's the plan: 1500GPH overflow, 15g DIY sump, skimmer, Knop "C" reactor, plus the return pump and plumbing of course. I was thinking of an Eheim, I need it to match or outperform the overflow right? What do you think of this? Am I missing anything?
<Eheim is a great choice, as for flow, see the above.>
I'm also going to the LFS to scope out their setups for plumbing ideas. Thanks again guys for all you do.
Craig
<Welcome, Scott V.>

Aquarium Setup and Pump/Overflow Questions 6/25/08
Hi there,
<Hello.>
I am in the planning of 40 gallon breeder with external coast to coast ( I like the setup and that there’s no space taken inside my tank) that goes to a 25 gallon sump. My plan is to keep softies and SPS corals with little LPS (if I cannot avoid the temptation @ all).
Anyways, I am planning to follow same system as http://www.reefcentral.com/forums/showthread.php?s=25431f8f03640480f5d7cce63c204925&threadid=1310585&perpage=25&pagenumber=1 with 1 inch drain pipes. To give you the brief summary, there’re two 1 inch pipe draining water but most of the work is being done by 1 pipe (3rd pipe is for fail safe). I had some questions over here:
1. I am planning to bring water back from sump to display via Eheim 1262. It’s a simple return from bottom that will split into 2 pipes (I need the size recommendation from you) and will be connected to ¾ or ½ inch LocLine (as you recommend) over the top. The pipes will move water upwards about 5 ft.
Do you think this will work?
<Well, yes and no. As far as the overflow, this employs one drain as a full time siphon, with the second gravity fed taking a bit of flow. The third is a gravity fed backup. The problem is that a gravity fed 1” drain can handle just a bit more than 300 GPH. The siphon 1” drain can flow 900 GPH or so. What happens when (not IF in my experience) the siphon to fails? The other two drains (one of which already had part of it’s flow used before #1 failed) cannot handle the flow. There are many of these “overclocking overflow” designs, all end up relying on a gravity fed drain for a backup. The reason is that the gravity fed drain is far and away the most reliable. If you have enough gravity fed backup capacity to accommodate the flow of the siphon fed drain if it fails, why have the siphon drain to begin with? It is an overflow design that does work most of the time, I am just not a fan of it after many (hundreds) of hours building and actually flow testing/trouble shooting overflows. In regard to the return, the issue with bringing it through the bottom of the tank is the potential for sump flooding. In the event of a power outage the water will siphon or simply drain down to the level of the sump output. Even if the return comes through the bottom and you bring it up, you risk the possibility of a leak in the line somewhere (LocLine is NOT watertight) leading to the same problem. All of this seems paranoid, but this stuff does happen, if you plan on having the tank for any length of time you will likely end up experiencing these events first hand.>
What size returns should I use?
<A few ½” or a single ¾”.>
Can Eheim handle such load and is it fine for this kind of setup for optimal working of sump (which may contain refugium to it too)?
<Yes, this is my personal favorite return pump.>
2. I am planning to add 2 Maxijets 1200 (modded) and two Koralia (need size recommendation) to move water inside the aquarium too.
Do you think it’s sufficient for SPS?
<Yes, definitely. You will not need so much flow, either the MJ mod.s (another personal favorite) or the Koralias (fours would be my choice) will be more than enough for a SPS tank this size. >
Do you think water will get too hot?
<It may, especially with the MH, time actually set up will tell.>
I live in Seattle so it really is not that hot over here except for occasional heat wave.
<The occasional heat wave is what can get you.>
3. I am planning to add 1 250 WH Metal Halide with 2 VHO on the aquarium as light?
Is the light sufficient?
<Oh yes, quite.>
Other questions may come up but I need your recommendation on #1 and #2 so that I can start ordering plumbing stuffJ
<OK>
Thanks
Ghazni
<Welcome, have fun setting up, Scott V.>

PVC Size/rate of flow 6/16/08
Hey All! I hope your Saturday is going as well as mine!
<Hello, it is/did!>
I am sorry to bother you with this, but I cannot seem to find the answer myself.
<No problem.>
I am in the plumbing stages of my 150 setup – it will be plumbed through the wall into a 120 refugium and a 55 sump. Can I tee the 2 x 2” drains from the 150 into a 3” to go through the wall or should I use 4” PVC instead?
<3” will yield enough flow to handle dual 2” drains.>
The answer will then allow me to determine how far from the wall the stand needs to be. I would hate to go with the 3” only to find it to be too small, and although it may be easier to just run both 2” drains through, I’m thinking that on pipe through will look much cleaner.
<Your choice, dual 2” lines may very well be easier to handle and setup.>
Thanks in advance for your help. I have been an avid reader of the FAQ’s for several years – the help all of you have provided me (and countless others) is so very much appreciated!!!!
<Thank you very much for the kind words. You’re welcome, always a pleasure to help, Scott V.>

Drains, Returns and Closed Loops, OH MY! 6/1/08
Hey Guys!
<Brian>
So here's where I am at and need some plumbing help. I have a 120g (48.5x24.5x24) AGA with center overflow that has a 1.5" drain. The tank is also drilled with 4 1" bulkheads along the back. I originally was going to use just the 1.5" to drain to the 40g breeder sump, and 2 of the back holes for returns with the other 2 for closed loop intakes, but after much reading on your site I think it might be best to change that train of thought.
So here is where I am at, and would love to hear your thoughts.
<Okay>
1.5" drain and the 2 outer 1" to drain into sump. That would put approx 2200ish gph into sump.
<Uhh, no... about half this at most>
So first question is with 5' of head, what should my return pump be rated at to handle that.
<I'd stick with about 1,000 gph maximum calculated>
Internal, external doesn't matter. I would run 1" return line back up T'd off to separate 20g fuge(this will gravity feed back to sump return area). The 1" return line would T off again up near tank and drop back over the top into tank.
The other 2 1" drains would T together up to 1.5" to feed into Dart pump for closed loop. I would run the dart up through a OM 4-way, 2 returns would come up over the top to the front corners with loc-line, the other 2 would come over the back of the tank, run along the very back inside the tank to the bottom middle on each side and come back up through the sand with more loc line to generate flow back up. I have to run the lines through the tank as the bottom is tempered and can't be drilled. The goal is to have no powerheads anywhere in the tank.
<Will, can be made to work.>
I am sure there is something I'm missing in here, so any help is appreciated.
Thanks,
Brian
<Just "missing" the estimate (of probable gravity/drain feed from the 1.5 and 2-1" lines) and need to consider the return in turn... all else reads as fine. Bob Fenner>

Bigger Overflow Holes 4/9/08
Hello Crew!
<Hello John.>
Thank you for all that you do. You are appreciated and admired by aquarists and fish everywhere!
<Thank you for the kind words and encouragement!>
I have one quick question. I have been reading, over and over, that in many instances, the diameter of the overflow holes on the A.G.A. MegaFlow systems [factory-ready] is not large enough.
<No, they are not really large enough.>
Can you/would you name a glass aquarium manufacturer, who makes standard-size/pre-drilled (reef-ready) tanks that have BIGGER diameter holes than those found in the A.G.A. tanks? I've done MANY web searches for this information, and I keep coming up empty.
<Most tank manufacturers will drill more/larger holes for you, for an extra fee of course. I have particularly found www.aqueonproducts.com (formerly AGA) to be great with their customer service. No long waits on the phone! Just give them a call and explain what you want, they will help you.>
Much appreciated. Have a great day.
John D.
<Welcome and thank you. Have a great day also, Scott V.>

Combining Overflows/Refugium Substrates 2/26/08
Greetings WWM Crew,
<Hello Bart.>
I have always enjoyed the hours I have spent reading on your site and the valuable info you provide. For this I offer my thanks.
<Thank you.>
I have a few plumbing questions for you regarding a system project I am undertaking. After three years of successful reef keeping in my 72 gallon bow-front I have acquired a pre-drilled AGA 120 and am making the switch. I am especially excited to do away with my siphon overflow (no major mishaps...Just lucky I guess).
<I hear you my friend!>
I will keep a variety of LPS corals on about 120 lbs of liverock and stock fish very lightly.
The tank is pre-drilled with two Megaflow overflow chambers installed. They have the standard 1" drains with Durso standpipes and ¾" returns. I understand from my research here that these are smaller than is to be desired, but my thinking is that I can get healthy water flow if I add some big powerheads in the tank and take care of filtration and skimming in the sump with the 12 or 1300 GPH I will get from the twin drains. Is this reasonable to assume?
<I am sorry, but no. These are smaller than to be desired, a 1” bulkhead will only flow around 300 GPH safely, giving you around 600 GPH total draining capacity.>
My plan is to place a 50 gallon sump in the basement, directly below the tank. If I were to combine the two 1" drains into one 2" pipe, will my drains slow down?
<This will work fine, the 2” has about 4-5 times the draining capacity as a 1”.>
I'm thinking it would be easier to send one pipe through the floor than two. The sump will be a simple design and house a skimmer (not selected yet) followed in line by a refugium. The return pump will be an IWAKI MD70RLT which should be able to handle return flow approaching 1400 GPH at the required head.
<You will want to choose a smaller pump.>
Since the combined flow to the sump directly below the tank should be around 1200 GPH, would this be too much flow for a refugium housing only Chaetomorpha?
<No, that is fine for the Chaetomorpha, but you will not be flowing this much.>
I am considering a sump with no substrate because I have heard that the substrate can become a nitrate factory. This is confusing because I have also heard that Deep Sand Beds are denitrifiers. What are your thoughts regarding refugiums without substrates?
<I like and use the DSB method. Substrate can become a nitrate factory when it traps excess detritus, usually a trait of large grain substrates. The use of fine substrates will not be an issue and will benefit your system with proper water flow, which you will need even if you leave the refugium bare bottom.>
My plan is that the Refugium and the skimmer would be the ONLY filtration in this tank.
<And the live rock in your display.>
I thank you in advance for any help you can offer. Keep up the good work!
Bart
<Welcome, will do. Scott V.>

Doing an Overflow "Calfo" Style 2/23/08
Hello Crew,
<Good evening.>
I've been reading and searching on WWM for my question to "Calfo" style overflows but can't seem to find the answer. I'm installing an overflow in the back of my 90 gal tank which has been drilled for two drains. Both drains are using 1 1/4" PVC attached to 1" bulkheads running to the sump.
<OK>
Due to space limitations where the tank is located the bulkheads for the drains are reversed ( flange on outside of tank) allowing the plumbing to fit closer to the tank. Thus this places the longer threaded end of bulkhead inside the tank.
<Not a problem.>
The bulkhead and PVC down elbow protrude approx 3 1/2" into the tank. If I install a "Calfo" style overflow obviously it will have to be at least 4 1/4" wide to allow for removal of the elbow if necessary but the question I have is how deep does the overflow have to be? How much water should be inside the overflow below the level of the drain bulkhead?
<You will want the inside bottom of the overflow to be at least 1 ¼” from where the water will enter the elbow in this case. This will allow unrestricted flow into the elbow. You can go deeper if you like, but it is not necessary. You may also be able to trim the bulkhead and elbow down a bit to get the width down a little.>
I was going to purchase an overflow that I could drill and attach to the bulkhead fittings but after some consideration on the hefty prices of the commercially available overflows, I'll make mine.
<I do sell overflows and do always encourage people to make their own whenever they are comfortable doing so.>
Any input on design considerations for my tank is greatly appreciated.
<It sounds like you have the right idea and a good plan. I will give you one tip from experience: If you do not go all the way from one side of your tank to the other, do be sure to leave enough room between the overflow and the side to fit in a magnet cleaner! It is all the small things that make life easier.>
Keep up the outstanding support.
<Will do, thank you, Scott V.>

Overflow Options 2/15/08
Dear crew,
<Hello James.>
I currently have a 300 gallon acrylic tank. 96x24x30 with two overflow boxes, 5x6 inches in each corner. I was planning on putting 2in bulkheads in each, but I can’t fit the 2in Durso standpipe in that narrow box.
<Bummer.>
I’ve trimmed the elbow and tee down so the standpipe now barely fits in, but I would have to drill the hole very close to the seam. I’m trying to get 3000gph through the tank.
Question#1 Should I get rid of the standpipe so I can keep the 2incn drains in the overflow box fairly centered and away from the seam.
< With this much water being moved it will be quite noisy without some sort of standpipe.>
Question#2 should I use the overflow boxes for the 11/2 returns and just drill
the back for 2-3, 2inch drains?
<If you are set on running 3000 gph through the sump then this is your best option.>
Question#3 If I drill the back, how far below the top seam would I have to drill for the 2inch bulkheads.
<I assume you intend to drill the back inside the overflow box? This will allow you to fit an inverted elbow inside the box to quiet things down. As for height you will want the top of the bulkhead to be a few inches down from the top of the overflow. Go too far down and you will hear the water falling inside the overflow. If you planned on drilling outside the box your height will depend on how you plan to set the drain up. If you just plan on running an elbow inside the tank you should drill fairly close to the top, but leave at least one hole diameter between the hole and any edge. If you plan on building a box for the overflow, then the same recommendations apply as above for the built in boxes.>
I would greatly appreciate your advice and opinion on this matter, thanks
james
<Welcome, good luck, Scott V.>

Horizontal Overflow 2/8/08
Hello!
<Hello Mike.>
I have a 75g tank I would like to use with a sump setup for an African Cichlid tank..
<OK>
I would like to try the "horizontal overflow", however, I'm not having a whole lot of luck finding any "standards" to go by for what actually "works best", such as, length, width, height, how far below the waterline you should place it, optimal bulkhead depth, (2) 1" bulkheads, or (1) 1 1/2" bulkheads?
<Nor will you…there are no such standards. Each individual application is entirely different/custom. The size of the box/weir will be dependent on how big you want it. As far as waterline it may take some trial and error. This aspect will depend on the size of the box you build and the flow running over it. If you run 1000gph over a 5”X5” box the water level is going to be higher than a 5”X10” box. The bulkheads are again totally dependent on your planned flow through them, but larger is usually better. As far as bulkhead placement, I would recommend you place the bulkheads as high up in the box as possible. If you place them too low you will hear the water as it falls from the top of the box down to the bulkhead’s level.>
If you could point me to some useful resources to help me in my planning, I would appreciate it.!!
<I build (and sell) a similar product to this. You can view my installation instructions in the link below to get some ideas regarding placement and size/flow. The general idea for your project is the same.>
Thanks for your time (and help)!
Mike
<Welcome, have fun, Scott V.>
http://www.momsfishsupply.com/overflowinstallation.html

100g Tank Transit Volume/Overflows 2/4/08
Hi Bob,
<Hello Lewis, Scott V. with you.>
The website is great but I was wondering if you could give me some advice about my current situation.
<OK>
I have a 100g tank given to me for free that was drilled with 2 x 1 inch holes at the waterline. I have a 500 GPH pump returning water from my sump, but because of the head, this is about 250 GPH. I would like a reliable method (ie. power cut tolerant) of draining water from my tank to my sump, without flooding. I know you have recommended 6 x 1 inch holes for a 180g in the past, but I can't drill my tank. I currently have a siphon set up, controlled by using a tap on the 32mm drain, but this is not practicable long term, as in the event of a power cut, my tank would drain about 15g into my sump with a total capacity of about 10g. So, which parts of my setup need I change/add? Many Thanks in advance! Lewis
<Your issue here is the transit volume, that is how much water is above the overflow, in the lines or gets siphoned out via your return line when the power is off, not the overflow itself. You may be able to lessen this by positioning the return line output directly below the water level in your tank or drilling a siphon break in the line. The transit volume will always be there, as a certain percentage of the tank volume, so it is likely you will simply need a larger sump for a tank this size. A note on the overflows, your 2X1” will easily handle the flow you are running and be far more reliable than the siphon type. Welcome, good luck, Scott V.>

Enough "fall" for Overflow 1/6/08
Crew,
<Ben>
Thank you in advance for you response. Before I go hole sawing through my living room wall, I thought I better run this by you. I'll try to ask this in a clear concise manner, but bear with me.
<OK, no problem.>
I have a 240gal. "through wall" set up, as in the display with stand & canopy is in one room, and everything else (sump etc.) is in the garage behind it. My concern is that the sump sits on a 30" high table and there might not be enough "fall" for the return lines. I have no experience with hydrodynamics, but do know that this depends on how much & over what distance, so here are the specifics. I have 4 X 1.5" drains drilled along the top back wall of the tank. My return pump is doing 2460 gph with my manifold configuration as is. (I've tested it several times) The drains, however, will only have about 10" of fall over a 10' span. Is this enough to keep up with the pump?
<Should be, 615 gph per 1.5” bulkhead.>
<<Mmm, what re the horizontal run? This may have a decided impact. RMF>>
I'm thinking that because I have some overkill on my drains, that I should be okay.
<The more the better.>
I guess the question boils down to how fast does water move downhill?
<The problem won’t be the 10” drop (you are not siphoning), it will be the 10ft run, that does decrease flow somewhat, but you will be fine here.>
I hope I made this somewhat clear... Any help would be appreciated. Thanks,
Ben
<Very clear Ben. Sounds like you are on the right track. Have fun setting up, it is one of the best parts of reefkeeping, Scott V.>

Re: FOWLR Setup for Messy Eaters 1/4/07
Thanks Scott for the response!
<Happy to help Brian.>
I was looking at drilling tanks and found that drilling tempered tanks (by me) may not be the best idea. I'd rather not have a glass "sculpture" in my
living room. (Maybe I can sell it off for millions as contemporary art?).
<The bottom is likely tempered. Do check with the tank manufacturer if your back is tempered, chances are it is not. You can overflow through the back too. If you find a buyer for such art, please let me know, I have many old tanks I can bust up!>
I was looking at hang-on overflow boxes. Would these work in conjunction with the LR to keep the water clean with messy eaters in it?
<It would work fine.>
I understand these work by suction, so it would be prudent to have 2.
<Highly recommended to have redundancy with these and any overflows.>
Do overflow boxes come with a GPH rating?
<They should, but the bulkhead the box uses on the backside is usually the true limiting flow factor with these boxes.>
How should I match it up with the return pump GPH rating?
<If you have two boxes, there will be nothing wrong with matching the pump’s flow at the head height you have to the full flow capacity a box/bulkhead. This will leave you with each box being able to handle the pump’s flow should the other box fail.>
For example, should one be higher than the other?
<If anything, have the pump flow less than the box/bulkhead can handle.>
Or should I just use a variable ball valve to balance everything out myself?
<If you get a larger pump than needed, you will need to. Don’t try to balance the flow right on the verge of what the box/bulkhead can handle. Leave yourself some margin of safety for things getting partially plugged.>
Scott also mentioned a filter sock. Is this just like what it sounds? A sock placed somewhere where water gets forced through it trapping particulates?
<Yes, usually the overflow line is dumped into the sock hung on the inside of your sump.>Thanks again guys! You've been very helpful!
Brian learning a little bit.
<Welcome, keep reading and learning, have fun, Scott V.>

Questions Regarding Overflows…(Another Unrealistic Expectation) – 12/26/07
Dear Crew,
<<Hello Brian>>
Hoping this correspondence finds all you fine ladies and gentlemen in good health, and enjoying a happy holiday season.
<<Mmm, funny you should ask as I’m still getting over a rather nasty bout with the ‘crud’ for the past 8-days … Not how I had hoped to spend my vacation...but happy nonetheless to be starting to feel “human” again. Thanks for asking! [Grin]>>
My question today is in regards to providing adequate flow through a 75 gallon reef system.
<<Okay…and I’m sure you’ve already read through our more than ample information on the subject>>
Rather than buying a grossly under achieving "reef-ready" system,
<<Hee-hee! I guess you have!>>
I've decided to go the route of purchasing a standard 75 gallon aquarium and having a go at drilling it myself.
<<Goodonya mate! Not such a tough task if you’re a bit handy…just be sure you get a tank that doesn’t have “tempered” panels where you plan to drill! Generally, on a tank of this size only the bottom is likely to be tempered. If purchased new, the manufacturer should have any tempered panels labeled as such…but it doesn’t hurt to contact them to be sure, especially with older/used tanks (assuming you can identify the manufacturer, of course)>>
After reading through the various FAQ's regarding overflow plumbing, and seeing the high praise and feedback that glass-holes.com have received, I'm inclined to go with their 1.5 inch through-the-back overflow system.
<<Okay>>
Per their website, they indicate that this should accommodate up to 1500 gallons per hour.
<<Hmmm, looks to me like this setup features a single 1.5” bulkhead…750gph is a more realistic expectation here, as well as a much more manageable flow rate re noise/sump plumbing simplicity>>
For safety's sake, I'm considering adding a second bulkhead/overflow to provide for a backup in the event that a blockage should occur.
<<Redundancy can be a life saver...>>
Since this is a system that is not dependent upon a siphon for facilitating the overflow, am I correct in assuming that any return pump should work provided that the rate does not exceed the overflow capacity?
<<That is correct…the return rate will match that of the pump rate…assuming, as you correctly stated, that the overflow rate of the throughput is not exceeded>>
The way I see it in my mind, the rate of the return pump would dictate the amount of water that would flow over the lip of the box, correct?
<<Correct…and thus you are likely also aware the “height” of the overflow box helps in determining the “running” height of the water in the tank…something to be considered when positioning the box>>
Sorry if this seems like a silly question, I'm just preferring to err on the side of caution as I only plan on doing this once.
<<No worries mate, well understood… Do be sure to plumb a gate-valve on the output side of the pump to temper flow if needed>>
Many thanks for your collective continued efforts,
Brian
<<A pleasure to help, do let me know if I can be of further assistance. EricR…back with the living>>
ScottV chimes in:
<The Glass-Holes.com kit mentioned does indeed include two 1 ½” bulkheads. It is actually the kit shown in the video on the same page. The picture/listing is generic…I will remedy this. Sorry for the confusion, Scott V., fellow crewmember and a partner in Glass-Holes.com.>

Re: Questions Regarding Overflows…(Another Unrealistic Expectation) – 12/26/07
Eric, Scott,
<<Brian>>
Many thanks for the clarification, and again for the excellent advice.
Cheers,
Brian
<<Ah yes, I am glad Scott stepped in to clarify/correct my perception of the "kit"...don't need any added confusion. Good luck with your project. EricR>>

Drilling overflows in AGA 12/16/07
Crew,
<Hello David.>
I just ordered an Aquarium Glass Diamond Hole Saw Kit from Diamond Tool King who advertises as one of your sponsors. I already paid for the purchase through PayPal. Do you know if Steve @ Diamond Tool King is legitimate? His prices are excellent, which sort of scares me. I hope his being one of your sponsors, or his advertising on your pages shows he is legitimate.
<No worries, the bits will work fine.>
Here is why I am ordering from him. I am setting up a reef tank starting with a 120 gallon AGA tank. I keep collecting pieces and parts, and reading and continually Reading and rereading. Sorry to say I did not find out about your site until a few weeks ago. I have now repeatedly read that the bulkheads holes are to small too begin to consider the tank a "reef ready Tank".
<Unfortunately the case.>
Yes I will, after tank aging, use the tank principally as a SPS tank, with a small scattering of LPS and even less soft corals. To date I have obtained two Iwaki 40RLXT's, Turboflotor 1000 with Ocean Runner 2700 pump for skimming, Aqualight Pro with two 250-Watt 10,000 K and two 96-Watt PC's. I also have a Megaflow Model 4 Sump, which had to be trimmed to even allow for the TurboFlotor. If I had known that drilling bulkhead holes was not such a great task I would have never gotten the MegaFlow sump. I might still replace it with a glass aquarium and place the baffles where they will work best.
<Whatever it takes to suit your setup, drilling the glass is fairly straightforward.>
I do not plan on using the Bio-balls that came with the sump so it might workout OK. I plan on about 100-150 lbs Live Rock some thing from at least three different areas. Probably large Fiji rock, Tonga shelf and branch rock and some other exotic rock. Now for questions and suggestions. I plan on cutting out the AGA overflow boxes and plugging the small bulkhead holes with plugged bulkheads. Yes I even footed the stupidly high price for two Megaflow overflow kits. Learning can be expensive!
<Learning generally costs something, whether it be time or money!!>
Anyway I plan on two 3 inch holes for 2 inch overflow bulkheads on the tank's back wall, giving a space of at least 3-3.5 inches between hole edge and tank inner wall. Top of 3 inch holes about 2 inches below tanks glass cover ledge.
<Sounds good, perhaps a little bit lower. General rule of thumb is one hole diameter away from any edge. Two inches down should be fine, but three will give you that much more strength in the end. Good choice on overflow size, plenty of capacity here.>
The return locations I am not sure of. With the tanks present setting viewing will be almost entirely through front wall of tank allowing me free rein to drill return holes in side wall which I believe would create better turbulent flow
possibilities due to the opposing flow from returns at both ends of tank. What do you think?
<I am not a fan of drilling for sump returns, at least not too far down due to siphoning issues.>
What with live rock, crushed coral, and live sand/gravel (from GARF) displacement eating up probably 20 gallons of space I figured targeting 2000-2100 gph for flow would probably be acceptable. Shouldn't be able to get around there with my two pumps returning through 1 inch PVC pipe and 1 inch bulkheads.
<Yes.>
I really don't know what would be optimum location for return bulkheads, ie. where on side walls. Middle of front to back? How far from top edge. How did I prevent back siphoning if pump power is loss.
<Yes, this is the problem. Some rely on check valves, but these are not to be trusted to work 100% of the time.>
I also have two Pan World pumps with 1 inch inputs and outputs that I could use for running circulation loop(s) or possibly throttling down one for use with a AquaC EV series skimmer if the TurboFlotor does not work out.
<A closed loop is the way to go here. You will be able to put the intake/return(s) where you would like to optimize flow (perhaps even use the predrilled holes for the intake). This will also allow you to run whatever flow through your sump you desire rather than running the tanks full circulation through.>
I also have a 1/4 HP chiller, lots of Maxi-Jets (900'sand 1200's) and two Wave Masters. Think I need to sale some circulation heads and wavemasters.
<It always seems like you can never have too many extra utility pumps!>
Is there any reason I should even consider putting return bulkhead holes in the tank backwall?
<Over the top will be fine. If you want to drill consider putting it fairly close to the top (again, at least one hole diameter from any edge) and use some Loc-Line for adjustability to minimize siphoning.>
Opinions and suggestions please, before I start drilling, that is if the diamond hole saws show up. Sorry this is so long, but I only have three weeks before school starts up again and I am really antsy to get started on this tank when I am not working.
<Nice project to work on with time off.>
Its been over six years since I last had a reef tank and things seem to keep getting better as time goes on. My last tank was a 125 gallon with a "high" turnover rate of 4 times per hour, 2 Maxi Jet 900's, a 20 gallon sump, 3 250-Watt 650 K halide shop lights, and a Kalkwasser drip. No skimmer, auto top off, CO2 calc reactor, hood with double ended halide bulbs, Actinic Power Compacts, LED moonlights. Things do change!!!
<Wow! They sure do.>
Thanks,
David E. Harris
<Welcome, have fun with your project, Scott V.>