New Tank Flow Problem…Powering The Return Manifold – 04/05/08
Dear WWM Crew,
<<Morning, Scott>>
I am setting up a new 90 gallon reef tank and installed a Calfo Manifold, which I think will work great.
<<If configured correctly, yes…I would agree>>
I love the clean design of the manifold.
<<Me too…solves the issues of powerheads in the display. Although it’s not suited to “every” application (e.g. – some living-area installations where a big/powerful pump might be too noisy)>>
The problem is I am using an Eheim 1262 pump as the return and am getting pretty weak flow out of the manifold.
<<Mmm, yes… These are wonderful pumps (and wonderfully quiet!), but after headloss I imagine you have little more flow than that need to power no more than a couple ½” nozzles effectively>>
Obviously, the pump is too small.
<<Agreed…and would help me greatly to know the size and number of output nozzles on your manifold. A good general rule-of-thumb is to allow 350+gph for each ½” nozzle, or 650+gph for each ¾” nozzle>>
I'm considering switching to a larger Mag-Drive, but I saw comment in a FAQ about using 2 return pumps.
<<Hmm…plumbed in what manner, I wonder?>>
I could add a second Eheim to the sump, but am not sure how to approach the plumbing into the manifold.
<<Plumbing the pumps in “series” might be the best configuration to reduce the likelihood of working the pumps against each other, though I think you will still lose some efficiency. I think you would be better off simply acquiring a larger pump suited to your needs/the requirements of the return manifold>>
This is the point where I could use some expert advice from the Crew.
<<My advice is use “one pump” of sufficient size, based on the guidelines for flow I have provided>>
Should I just go to the larger Mag-Drive, or add a second Eheim to the mix and plumb it into the same return line as the other Eheim?
<<The first option>>
How many GPH do you recommend to get adequate flow from the manifold so I can be forever free of power heads?
<<As I indicated above, you need to provide more info for me to make a recommendation here>>
This being a new tank, I really want to get it right before starting to add stock.
Thanks much for your help,
Scott
<<Happy to assist, Scott…and do write back with the specs of your project for further discussion if you wish. EricR>>

Re: New Tank Flow Problem...Powering The Return Manifold - 04/06/08
Thanks much, Eric.
<<Welcome, Scott>>
I have 4-1/2" nozzles fitted with Loc-line fittings with valves to adjust the flow as needed.
<<Ah, okay…then you need a pump that will provide at least 1400gph, after headloss. I recommend getting something in the 2400gph range and installing a gate-valve on the output side to adjust flow if needed. Better to go bigger than you need and temper the flow than to go too small. Besides, you will be glad to have the extra power once the plumbing lines coat with organic matter…you can simply increase flow with the valve to compensate>>
The output from the pump is 3/4" feeding into 1/2" line for the manifold. I am also bleeding off some of the main pump flow into a refugium.
<<Mmm…all the more reason for a larger pump>>
I'm thinking to pursue a Mag-Drive 18 pump, which produces 1,375 GPH at 4' head (according to the manufacturer).
<<Too small…I think you will be disappointed in the performance of the manifold with this pump>>
I think the Mag-Drive 24 might be overkill, but I would hate to under-buy AGAIN!
<<Indeed>>
I also have to be careful of overwhelming the overflow (single 1 1/2" drain).
<<Ah well…this “is” your limiting factor. The single 1.5” drain means your flow is restricted to a mere 700gph…not nearly enough to power the return manifold. To make this work, you will need to plumb the manifold as a “closed-loop” rather than an open-loop through the sump>>
I also looked at the Ocean Runner 6500 (1700 GPH) based on some posts in FAQ's. I'm not as familiar with these pumps.
<<A very good brand of pump, in my opinion…and preferred over the Mag-Drive but for the size limitation>>
Of the two, what would be your preference?
<<As stated…you will need to go with the larger Mag-Drive, and plumb the manifold as a closed-loop>>
Thanks,
Scott
<<Happy to help…if you have more questions re the closed-loop, you know where to find me. Eric Russell>>

Plumbing A Closed-Loop Manifold – 01/15/08
Hi Crew,
<<Hello Jim>>
I've been reading Anthony's page about a closed-loop return manifold, and I am planning to build one.
<<Neat... Can be quite useful>>
I just had a couple quick questions after reading the article.
<<Okay>>
First: I have a Perfecto 150H "Reef Ready," which is woefully inadequate, as Anthony said. It had one overflow, with a 1.25 inch drain and a 1" return.
<<Hmm…but still, better than those “other” reef-ready with 1” drains and ¾” returns that abound>>
Warns to run no more than 600 GPH.
<<I’m impressed…most would state about double this…though I’m inclined to say something closer to 500gph would be prudent>>
Well, I slightly widened the slots in the outer wall, and slightly lowered the top of the inner wall, and drilled another air hole in the elbow at the top of the drain, and I think I am draining closer to 700GPH, but that's maxed.
<<Really? But at what cost (noise/bubbles)? Do perform a test to confirm to confirm (time the filling of a vessel of known volume)…I would be interested in your findings>>
Since I am planning a manifold return, and am setting up a DIY recirculating skimmer, which I would love to simply gravity feed, is there some particular reason why it would be a bad idea to cut the top off the return, maybe 1.5-2 inches below the opening on the main return, and use it as a bubble-free drain for the skimmer (with a valve)?
<<You mean as in having the tank drain flow directly in to the skimmer? Nope, I don’t think this is a bad idea at all…assuming the skimmer is designed for such>>
Second: I am planning a complete loop around the top of the tank, as suggested. I was planning to include 9 tees--four across the back, one at each end, and three across the front. I was planning to use 1/2" PVC or even CPVC to extend two of the tees down behind the rockwork, where elbows could be used to direct some water around inside to clear out detritus.
<<Mmm, I don’t think this will work as desired. The resistance/backpressure from the water in the pipe extended below the waterline will render the flow all but useless at these two nozzles. If you wish to do this, the two “submerged” nozzles will need to be isolated from the rest of the loop and provided with their own pump>>
I was going to use loc-line on the remaining seven, with flat flares on the rear two and round nozzles on the sides and front. Is there any reason not to do the "down behind the rockwork" thing?
<<Only for the reason stated…but can surely be done as a “separate” closed-loop>>
Is 7 nozzles too many?
<<Seven nozzles are fine…though the efficacy of this closed-loop will depend on the size of the pump employed. ½” nozzles will require a pump capable of providing at least 350pgh “per nozzle” after headloss. ¾” nozzles will require at least 650gph per nozzle after headloss>>
Would 1/2" loc-line be adequate, or would I need to use 3/4" (1/2" is so much cheaper, but I don't want to invest so much time and effort and go too cheap on the nozzles)?
<<1/2” will be fine…>>
I am using a submersible pump rated for 1300 gallons, which I figure should be pumping 900-1000 gallons when I am done.
<<Mmm, that means no more than about two ½” nozzles on the loop else flow will be “feeble” at best. To provide adequate flow volume to seven ½” nozzles, you will need to start with a pump in the 3000gph range…maybe larger, depending on its power/susceptibility to headloss>>
Thanks so much!
Jim
<<Happy to assist. EricR>>

Re: Plumbing A Closed-Loop Manifold – 01/15/08
Hi Eric,
<<Hey Jim!>>
I also like the idea of gravity feeding the skimmer directly off the tank; my specific question was: is there any reason it's not a good idea to chop the top off the "return" and use it as a drain?
<<Ah! Sorry mate…didn’t “get it” the first time. And to answer your question…no reason at all “not” to do as you describe. Of course, I’m sure you understand this means you will have to fashion some type of “over the top” return from the pump>>
As for number of nozzles, ½” should have 350GPH each?
<<Afraid so…if you wish to have any kind of force/useful flow from the nozzles>>
Because I was planning to run this manifold using the return off my sump, but I know there is no way I will get much over 1000GPH input, even using both bulkheads for drains, and I don't have any additional drains right now.
<<Mmm, yes…and do understand, a “return manifold” does NOT constitute a closed-loop when fed from an open sump return pump (the word “closed” is quite definitive here). This changes things greatly as you are no longer limited by the size of the return pump, but rather by the size/capacity of the drains leading to the sump. In your case, if you use both throughputs (1.25” & 1”), you will be limited to something in the 800gph range after headloss…meaning two ½” nozzles on the manifold, at best>>
I guess I could set this up as a separate closed loop, isolated from the sump return?
<<To be a “true” closed-loop, yes…and to get the flow you want, definitely>>
How would I plumb the intake?
<<Best done through the side/back of the tank. It can be placed as “deep” as you like, though you should keep access for maintenance/clearing blockages in mind before burying it at the base of the live rock>>
The tank is already running, and I am too scared to drill it anyway (took three years of saving my pennies to get it).
<<Pity…is easier than many folks think (and only requires a “partial” drain of the tank)…but I do understand your hesitation re>>
An overflow (or several, more likely)?
<<Theoretically, a feed to the closed-loop pump via a siphon overflow “is” possible (plumb the pump directly to the bottom of the external box), but finding one suitable for the typically high flow rates involved will be a challenge for sure. Perhaps a DIY rig spanning the length of the tank back and fed by a dozen or so 1” siphon tubes (number depending on pump flow rate) spread along that length…but, this would have the potential to be very unsightly from within the tank…and probably a maintenance nightmare to keep all the tubes running>>
Thanks again.
<<Hope this proves helpful…do let me know if you want to discuss other options. I will state that for tanks of this size and somewhat larger, requiring several to even a couple tens of thousands of gallons-per-hour water flow…nothing beats Tunze Stream pumps for high-flow efficiency, power savings, simplicity of installation, and quietness of operation…in my humble opinion. Regards, Eric Russell>>

Closed-Loop questions 1/11/08
Crew,
<Joe>
I am currently in the process of setting up a 210 gallon AGA tank. I want to drill the tank for two different closed loop systems. The first will be a spray bar along the bottom of the tank that the live rock will be built up around. (was thinking that I will run this in 3/4" PVC with a flow of about 1500gph or so)
<I would make it 1” pvc for this flow.>
This will keep the rock from building up wastes. The second will be a system of Anthony Calfo's design around the top of the tank. (was thinking that I will run the manifold in 1" PVC with 1/2" nozzles, or should I go with 3/4" nozzles?)
<Depends on the number of output desired. For 3500 gph I would go with five ¾” or eight to nine ½” outputs.>
(If I go with 1/2" I am figuring about 10 nozzles for a flow of about 3500gph, 350 per nozzle) That said, my questions are these; can I run both loops off of the same pump?
<Yes, with the amount of outputs a very large pump.>
I would much rather purchase one pump than two since they are not cheap. I was thinking about running both loops off of a Sequence Hammerhead pump with ball valves on each loop so that I can adjust the flow Going to each. Will this work or would I be better with two separate pumps?
<Two pumps has its advantages. If one pump fails you still have circulation while waiting for a replacement/repair. Consider running two Darts, or even a Dart and Snapper for this application, this will make intake plumbing easier also.>
Where should I place my intakes? I would like to hide them but then again I don't want to tear my reef apart to clean them so I was thinking of just putting them about 3/4 of the way up the back of the tank.
<I would be sure to place them in a position for easy cleaning.>
What size should the intakes be and how many? The hammerhead has 1 1/2" threaded connections so I was thinking that I would have 4 intakes drilled in the back of the tank for 1 1/2" or even 2" bulkheads and tie them all together to feed the pump.
<I would opt for two 2” intakes here. The same for the dual pumps.>
This way the flow at any one intake is not enough to suck up any animals. So the back of my tank would like something like this,

_______________________________________________
[ ]
[ X X X X ]
[ ]
[ ]
[ ]
[ O ]
[______________________________________________]

In this simple diagram the Xs are my intakes and the O is my return for the spray bar (should I make the spray bar return an 1 1/2 bulkhead and then choke it down or should I choke down before the bulkhead?)
<After the bulkhead.>
The return for Anthony’s loop will come up over the back of the tank.
One other questions, I have not yet purchased the skimmer for this tank. I want a really powerful skimmer as this will be a almost entirely SPS tank, I was thinking of a ASM G-5 or a Lifereef VS3-36. What skimmer would you recommend for this tank?
<I really like the ASM skimmers, I would also be considering a Euro-Reef as well.>
Thanks for all your help.
Joe
<Welcome, good luck, Scott V.>

Spraybar/Closed-Loop Questions – 01/08/07
Crew,
<<Hiya Joe>>
First I just want to say that the web site is fantastic.
<<We’re pleased you think so>>
I have found it a great resource as I have been setting up my various tanks. I am currently in the process of moving up from a 90 gal reef to a 210 gal AGA Mega-Flow tank.
<<Excellent…and since you have been reading, I assume you know how many of us consider the “Mega-flow” moniker to be a misnomer>>
The tank is going to be a mostly SPS dominated tank so I want to have two separate closed-loop systems in the tank.
<<Okay>>
One will be a spray bar system that the live rock will be placed around to keep waste from settling anywhere in the rock. My questions on this system are; where should I place my intake (could it be placed inside the Mega-Flow to hide it or would the Mega-Flow not be able to keep up?) and how large should the intake be?
<<Don’t place the intake for your closed-loop in the drain overflow box…the box is not designed to handle the additional flow. Otherwise, you can position the intake anywhere you like…though low-down on the back/sides will likely be easiest to hide/disguise. As for size…match the closed-loop intake to the size of the pump intake>>
How large should the piping for the whole spray bar be (I was leaning toward 1")?
<<For the spraybar itself I would think ¾” pipe would be sufficient, as well as less obtrusive. The pipe feeding/leading up to the spraybar should be “at least” as large as the pumps output nozzle>>
How large will my pump need to be (I was think something around 3500gph)?
<<Generally, the size of the pump for a closed-loop is determined by the number and size of the flow nozzles…but a spraybar will not be so easy to calculate I think. Obviously the size and number of perforations in the pipe will ultimately determine the “force” of the flow…and is quite easily adjusted for here as compared to a conventional “loop.” I think you can use about any size pump you like and “experiment” with the spraybar to achieve the best results re. But personally, I think 1200-1500 gph for the spraybar would be sufficient…reserving the/a larger pump for your other closed-loop>>
Should the spray bar be fed with one or two returns?
<<Either way is fine, though a “pair” of returns to feed the pump offers some redundancy as well as a decrease in suction/danger to your livestock>>
Lastly, is this system compatible with a deep sand bed (I feel like it should be as long as I lift it 5" or so off the bottom to allow for the sand and keep the holes pointed up)?
<<Indeed…as long as you take the flow direction in to consideration as you mention>>
The second closed-loop system will be of Anthony Calfo's design along the top of the tank to provide random flow.
<<Excellent>>
My questions for this system are the same questions about intake (placement, size).
<<And my answers are the same>>
The same question about pump size?
<<As stated…determined by number and size of flow nozzles. You should figure (after headloss) about 350gph per ½” nozzle and about 650 gph per ¾” nozzle in order to achieve enough “force” to create a purposeful flow>>
How many nozzles should be on the system (the tank is 6' x 2')
<<I would employ at least six…eight if you have the pump for it>>
What size should the piping and nozzles be (I was thinking 1" or 1 1/2" piping to 3/4" nozzles)?
<<Again, match the feed pipe to the output nozzle of the pump (or slightly larger if you wish). The ¾” nozzles will be fine if a large enough pump is used, but on all but very large systems my preference is to use ½” nozzles…less intrusive, more forceful flow, can add more per a given pump size>>
Do you think that this is a good setup for a SPS tank?
<<Match your nozzles and pumps correctly and these closed-loops should serve well>>
Please let me know if there is some way better for me to be doing this.
Thanks so much for the help.
Joe
<<Happy to share. EricR>>

Drilling For A Closed-Loop...Use The Correct Bit Size – 12/12/07
Hello,
<<Hiya Steve>>
I recently purchased a used 100 gallon long tank (60” x 20” x 20”) and am in the planning stage. I would like to bring the tank to my local glass shop to have it drilled for the closed loop. (I really like the neat appearance of a tank with a drilled closed loop & no power heads or PVC to look at.) I will be using a Pan World 50PX-X external pump. I calculate around 775 gph after head loss.
<<Hmm, with this flow rate you should only expect to use a couple ½” nozzles or a single ¾” nozzle for the return, and still have any useful force/strength to the flow. A good rule-of-thumb is to figure 350gph per ½” nozzle and 650gph per ¾” nozzle. Much less than this, and the water won’t exit with enough “force” to have much effect>>
(My return from the sump will be running through a Mag 9.5 and should turn around 570 gph after head loss.) I am planning to drill three holes in the back glass for 1” bulkheads.
<<This size throughput should be fine for the closed-loop, but do consider 1 ½” bulkheads or larger for any “gravity” drain lines>>
One will be an intake with an overflow strainer located dead center, about 1/3 of the way up from the bottom of the tank. (Should I use two intakes instead of one?)
<<One throughput for the pump intake is fine, but to minimize effects from obstructions/blockages, consider using a wye-fitting and “two” bulkhead strainers to supply the intake>>
The other two will be returns drilled 2/3 of the way up 15” from either side. Problem: My local glass shop only has a 2” drill bit and the manufacturer of my bulkheads suggests a 1 ¾” hole.
<<Yes...this is the correct size for the fitting>>
It seems to me that the 2” inch hole may work, but I would like a second opinion on this. I have successfully used a one inch bulkhead in a 2” hole on a 29 gallon tank, but this tank would be much more expensive to replace if a problem occurs.
<<I don’t recommend this, the 2” hole provides too much play/removes too much material behind the rim/lip of the bulkhead for a strong and secure seal. Best to use the correct size bit for the bulkhead. A correct bit can be purchased for around $50...perhaps you can offer to buy the bit and let the glass shop keep it for drilling the holes...>>
I have also considered just drilling one hole for the intake and running the returns over the back, although this is not my first choice.
<<This will work...though I like your first option better>>
Thanks for taking the time to guide me.
<<Hope it helps>>
Your advice is greatly appreciated.
Steve
<<Happy to share. EricR>>

Re: Drilling For A Closed-Loop...Use The Correct Bit Size - 12/12/07
Thanks for the great help!!!
<<Hope it proves worthy>>
I took your advice and ordered the 1 3/4 inch bit.
<<Ah, very good mate>>
I do plan on using 1/2 inch nozzles on the two returns from the closed-loop.
<<Is best>>
Do you think that 775 gph (after head loss) will be sufficient?
<<This will depend much on species kept, placement in the tank, aquascaping… But coupled with the flow from your sump return it will likely be fine>>
I don't want to add powerheads to the tank later.
<<Understood>>
(My inhabitants will be mostly softies that I will transfer from my 55 gallon. Here is a pic of my 55 http://i225.photobucket.com/albums/dd214/SFontana1/55-1.jpg.)
<<Very nice, though if I may… That Rose Anemone should be in a tank of its own… And the Sun Coral colony will require direct feeding for long-term health…>>
The 100 gallon tank I purchased is reef ready.
<<Yes, well…a common misnomer>>
It came with one corner overflow, containing a 1" drain and a 1/2" return.
<<My case in point… These throughputs are hardly adequate on their own for reef type flow, like the term “reef ready” would have you think. Consequently, these throughputs will limit the size return pump to something that will provide no more than 300gph after headloss>>
If both bulkheads were one inch, I would make them both drains. Would it be worth it to convert the 1/2" bulkhead to a drain??
<<Only if you want to maximize the capacity re…though any increase will be very marginal with the addition of a ½” bulkhead drain>>
I guess I could always drill another hole on the opposite side of the tank close to the water line for a second drain and use a strainer fitting.
<<Ahh…now you’re talking!>>
What would you suggest?
<<Another 1 ½” bulkhead to supplement the drain, as you describe>>
Thanks for taking the time to help.
Steve
<<Always a pleasure. Eric Russell>>

Water return manifold question 10/31/07
After reading Anthony's article "Plumbing a Water Return Manifold - goodbye powerheads!" I decided to have a go at it. I found it to be rather loud, so I inserted PVC into the "T's" so that the water would flow into the tank below the water line. This solved the noise problem (along with the stand pipe I found out about here-thanks!). But my question is: without agitation at the surface, will there be enough o2? Even with the overflow box there seems to be no water movement on the surface. If I take out the PVC (so water comes into the tank above the surface) there seems to be enough movement... but then there's the noise again. If the pump is sufficient to turn over enough water per hour, should it matter if the surface of the water is smooth?
<Hi Jen, you will lose some gas exchange with the calmer surface. It really shouldn’t be a concern with adequate flow through your overflow and skimmer. If you wish to keep it quiet and agitate the surface you could put a 45 or 90 degree fitting on the end of one of the pipes and angle it a little towards the surface or get some Lockline which will allow you to easily put each output wherever you would like. Some actually advocate for a calm surface to increase skimmer performance (surface water being more concentrated through the overflow to the skimmer).>
Thank you in advance for your answers and for providing a wealth of information here! Jen
PS- yes, if a woman can plumb this manifold thing anyone can do it
<Thank you very much. The two best reefers I know are women. Their tanks are the envy of all the locals here. If only my wife will plumb my next project...Scott V.>
<Jen, I wanted to edit the spelling of the plumbing product I referred to, it is Loc-Line. Thanks, Scott V.>

Manifold Question...Flow Rate/Velocity vs. Nozzle Size – 10/04/07
Crew,
<<Hello...whoever you are>>
Thank you in advance.
<<Happy to help>>
I am in the process of setting up a 240g. fish/reef set up. I have acquired the Dolphin AMP 4000/3000 for my return pump. It can pump more GPH using a 2" return line.
<<Mmm yes, 4500gph...but starts to fall off quickly with head pressure/height (4000gph at only 2ft of head height)>>
The tank is an acrylic with four equal sized cut outs on top to accommodate my four MH lights. I am planning on splitting the return line into two lines, then two off of each of those two, that will then terminate with one return at each of the four cut-outs.
<<I see>>
Should I reduce the four terminations to 1.5" or smaller or leave the whole manifold piped at 2"?
<<I would at least reduce the terminations/nozzles. Let’s figure with subsequent head-loss from the plumbing configuration that flow will be reduced to at least 3000gph en toto...maybe more. A ¾” nozzle requires about 700gph to produce a useful “velocity” for what you intend, so this is what I suggest you use (4ea. ¾” nozzles at 700gph = 2800gph minimum total flow required). If you find that your total water flow is reduced further than this then a ½” nozzle may be required...or switch to a pump with a better pressure rating>>
Will 1.5" give more pressure to better reach the depths of the tank?
<<Not at the terminal ends/as a nozzle size...as explained>>
My concern is that if I leave all 4 outputs at 2" the GPH will remain the same but the water will simply be falling out of each return with not much pressure to agitate tank water.
<<Exactly>>
What do you think?
<<You have my thoughts re>>
Thanks!
<<Quite welcome. EricR>>

Some General Questions On Sump/Closed-Loop Plumbing – 07/03/07
Hi.
<<Hello>>
I was wondering if you could please answer a few quick questions regarding plumbing.
<<Sure…ask away!>>
I am setting up a 135-gallon reef with 55-gallon sump.
<<Very nice>>
Currently the tank has 4-holes drilled in the upper back glass panel that fit 1-inch bulkheads.
<<Okay>>
I'm planning on using all 4 as overflows out of the tank.
<<Do figure only about 300gph per…still, 1200gph is a LOT of flow to process through the sump (if that is your plan)>>
I was planning on plumbing 2 of the overflows down into the sump where an Iwaki rxt30
<<I think you mean the 30RLXT?>>
(19 gallons/minute at 0 head) will return the water back into the tank (approximately 5-feet head).
<<Be sure to plumb a “gate-valve” on the output side of the pump to allow tempering of the flow if necessary>>
The other 2 overflows I planned on incorporating into a closed-loop system with another pump similar to the Iwaki with similar flow rate (I don't have it yet).
<<Ah! Excellent…but you really only need one of these throughputs for this purpose>>
Would the two 1-inch overflows per pump be sufficient to minimize sucking and gurgling noise, or should I plumb all 4 overflows down into the sump, forget about the closed-loop and use some powerheads instead?
<<If you keep the flow rate for the sump drains in the range I suggested you will likely be fine, although even then sometimes a bit of tweaking (aspirating the lines, experimenting with different configurations of the termination ends, etc.) can be necessary due to the vagaries of system design. As for the closed-loop, a single throughput directly plumbed will be enough to supply the pump (the fluid dynamics are different than those associated with “gravity” drains). You could use the last bulkhead to supply the sump and be even further ahead of the game…or even use it to supply an in-line refugium>>
Or even a third option: use 3 overflows for the sump and 1 for a closed-loop with a smaller pump?
<<You can do this with you current planned pump. Unless there is something about your design that will restrict the water volume (e.g. – bushing “down” the pipe size), as long as you match the bulkhead/pipe diameter to the intake port on the intended pump you should be fine>>
What size (flow rate) pump would work ok with a 1-inch overflow to minimized gurgling and sucking noise?
<<As explained…unless the throughputs are positioned very close to the surface where a very strong pump/flow rate may create some cavitation. But again, be sure to plumb a gate-valve on the output side of the pump>>
Also, on the return plumbing from the sump (and closed-loop if there will be one) should I reduce the 1-inch return pipe just before it enters the tank after the T, or should the two pipes putting water into the tank remain 1-inch (the output on the pump is 1-inch)?
<<Reducing the diameter as you indicate often makes the return easier to handle/place/disguise, but will also reduce flow/add to head pressure…as will that “T” you mentioned. All the more reason to slightly oversize your pumps and adjust flow with the gate-valve if needed. For the closed-loop, to will need to reduce the terminal ends/nozzles to ½” to achieve a useable velocity…and then likely no more than two of these (for closed-loop applications figure about 350 – 400 gph per ½” nozzle)>>
Lastly, should the bulkheads be slip or thread on the outside of the tank portion?
<<Is up to you>>
I want thread so they can easily be removed just in case, but am worried about leaks.
<<I wrap my threaded fittings with several layers of Teflon tape…or you could smear some silicone sealant on the threads just before assembly and let it cure before use (this doesn’t “glue” the joint but does help greatly with creating a drip-proof seal>>
Your expert opinion would be greatly appreciated here.
<<Mmm, don’t consider myself an expert…but prefer to think of myself as a “student” of the hobby>>
Thank you
Jon
<<A pleasure to assist. EricR>>

Closed Loop Filtration, SW "filtration"...    5/24/07
Hi Crew!
<Ryan>
I'm going to be building a FOWLR aquarium that has a requirement of four viewable sides. This means no overflows.
<Mmmm... not really>
I'm going to have to run the plumbing directly out and back in through the bottom of the tank.
<See>
I've seen this done using UV and Canister filters inline, however those two aren't my first choice of filtration. I would like to have a refugium on it, but I'm not sure how that can be done with a closed loop or with all of the plumbing coming out of the bottom.
<Not with a "closed" plumbing arrangement... but one that is "open", sure. You can/could have both types... two separate sets of plumbing...>
If a refugium is not a possibility, what are some other filtration mechanisms I could consider?
<Heeeeee! Please read here: http://www.wetwebmedia.com/marsetupindex2.htm>
Thanks!
Ryan
<Welcome! Bob Fenner>

Re: Closed Loop Filtration   5/24/07
Bob/Crew,
Thank you so much for your reply!  I have three addendum
questions.
I realize I could send overflows up through the bottom of the aquarium
to the place where I would want the water line, near the top of the tank.  However, this tank is going to be four feet tall.
<Height doesn't matter... functionally... Are you concerned re appearance?>
  (55"L x 24"W x 48"H)
<Yikes... hard to aquascape and maintain...>
So my questions are:
1)  In your esteemed opinion,
<Steamed more like it>
would glass be a better cost conscious option over 1.25" acrylic for a tank this tall?
<Mmm, posted... I would go with acrylic myself...>
2)  Would you use an internal overflow for this setup to have better gaseous exchange/oxygen saturation?
<Mmm, better than what? Likely not an issue here unless the power goes out or there is a pump failure...>
3)  What would be a good method to make a 3'10" overflow and return look "natural"?
<A bunch of possibilities... one could attach phony corals, pile up real or faux rock about...>
I'm thinking I could build  pvc structures like the one I have below (best I could do with clear text) and zip tie live rock around the pvc (not drilling through the pvc).  This would give it an arch like feel and I could hide the plumbing for the closed loop canister filtration in here as well.
<Yep>
Overflow on left, return on right.

       |                     /


      /|                    / \


    /  |                   /    \


  /    |                  /       \


/     |                 /         \   


|      |                |           |


Thanks again for your time and sharing of knowledge!
Ryan
<A pleasure to share... I would also like to add that if it were mine, I'd "sleeve this overflow... to "make" the discharge water come from near the bottom... have an outer pipe notched at the bottom, going over the internal stand pipe... this one could be drilled to accommodate the zip-ties... Bob Fenner>

Manifold Question. Siphon-Fed Closed-Loop – 05/23/07
Hi: Joe here.
<<Hello Joe...Eric here>>
Thanks for all your valuable information.
<<Quite welcome...is a collective effort>>
I have a 90-gal tank that I would like to add a "closed-loop" system to.
<<Okay>>
Like many people out there a drilled tank is not an option.
<<I see>>
Anthony’s remarks tell me he hates over-the-tank-lip systems to an external pump, lots of us have no option.
<<Agreed and agreed...even if not for the best reasons in some cases>>
Other members of the crew say it will work.
<<Mmm, I think even Anthony will concede they work...for a time.  The inarguable truth about siphon overflow systems is they will fail sooner or later.  But, there “are” things we as aquarists can do to mitigate this hazard.  Obviously, daily (when possible) checks of the system to note a decrease/loss of siphon are critical.  But the truly wise hobbyist will also plan for/employ redundant systems (a concept I’ve come to appreciate much more just lately).  Providing more than one pump input siphon will also reduce the amount of suction/pull at each intake, thus reducing the hazard to your fishes/motile inverts>>
I plan on using a Mag 3400 with a 1" intake.
<<Danner Supreme doesn’t manufacture a 3400 model of the Mag-Drive pump, you must mean a 3600.  But that aside...pulling this much water through siphon overflows is going to prove interesting I think...please do let me know how things go>>
The outlet will be 1" up to the tank, then to 3\4" manifold and 1\2" at the nozzles, 6 nozzles.
<<Expect to need about 350gph “per nozzle” after head-loss, to get any kind of meaningful flow>>
Is my plan ok?
<<Mmm, maybe...though I don’t think I’ve ever seen this done this way before.  How do you plan to protect the intakes of the siphon tubes?  I don’t think using a skimmer box is practical giving the amount of flow...perhaps it is best to simply install something like the screens used on bulkhead fittings>>
I know over-the-tank-lip is not the best, but this is my only choice, isn’t it?
<<Can’t say...you haven’t provided enough detail about your tank/setup.  If all the tank panels are tempered then yes, this is about the best you can do aside from going with internal mechanisms like the Tunze Stream pumps.  If the tank is not tempered then what is preventing you drilling the back panel?>>
Some suggestion is putting the pump in the tank, but this pump draws 380 watts, and I thought heat could be a problem.
<<Agreed...along with the trouble of trying to hide/service the pump in the tank>>
Thanks again for all the great information.
<<Happy to assist...and as stated, I would be interested to hear how this project turns out.  EricR>>

Return Manifold and Pump Size? - 03/03/07
Hello to all and thanks in advance,
<<Howdy…and you’re welcome>>
In an effort to rid me tank of annoying power heads and lower temps I am building a closed-loop water return manifold in my 55 gal tank (48”l x 12”w x 20”h).
<<Ok>>
The tank is un-drilled so until I move out of this limiting apartment and upgrade I am sumpless (I refuse to use an overflow box with J or U tube because I would like my security deposit back when I leave).
<<Hee…indeed!>>
I am building the system out of ¾ in. PVC tubing and fittings, and going down to ½ in. at the 45 degree elbows coming out of the T’s.  There will be 10 outlets (4 on the front and back and 1 on each side) with at least 3 or 4 of these being plugged up to allow for changes in flow when needed later on.
<<Ah…good idea>>
The pump is either going to be directly behind the tank for ‘0’ head or on the floor below with 53 in. of head pressure needed.
1- I am trying to find out what size pump would be needed for something like this.  I am thinking in the 1200 to 1500 GPH range.
<<Figure “at least” 250 gph per ½” nozzle, plus another 20% for the eventual bio-film buildup in the manifold piping and this means you need a pump that will provide a minimum of 1800gph “after” head-loss (This is assuming only six of the ten nozzles will be open at any one time…otherwise calculate as necessary)>>
2- Do you think this will be adequate or overkill?
<<Will need to be a bit more in my opinion.  But do be sure to plumb a “gate-valve” on the output side of the pump to temper flow if needed>>
The tank houses 4 damsels and a blue spotted sharp nose puffer (I know he is not reef safe but he is oh so cute and has yet to even looked twice at any of the corals  <<yet>>), various inverts and some corals (whose numbers seem to be increasing…ahh the addiction)
3- Also in purchasing the pump should I be purchasing one rated for pressure or one for free flowing circulation?
<<I would consider a pressure-rated pump for the closed-loop…though a “large enough” non pressure-rated pump will work>>
I am looking at the Japanese Iwaki pumps for more than one reason, choices are:  the MD40RLXT which is a circulating pump rated at 1,200 GPH, and either the MD55RLT for pressure rated at 1,080 GPH or MD70RLT – 1,500 GPH.  What do you think of these choices?
<<All great pumps but…  The 70RLT should work if you’re willing to cap off a one or two more nozzles than originally planned, but I think you would be better off getting the 100RLT for your planned configuration>>
4- Considering heat transfer and electrical usage do you think it is worth my time to also be looking at MAG drive pumps?
<<The Japanese motored Iwaki pumps are fairly economical to run and also surprisingly cool in my experience and would be my preference here>>  
I won’t be having any other pumps running except the MAG – 3 drive that is on my AquaC Remora Pro protein skimmer.  I would rather not be paying an arm and leg each month to run the tank, but I also don’t want to make soup of my tank with super high temps, especially come summer time.
<<Understood.  Don’t discount the effectiveness of evaporative cooling…install a couple fans to blow across the surface of the tank to help keep water temperatures down>>
Once again thank you,
Randy
<<Happy to share.  EricR>>

Re: Return Manifold and Pump Size? – 03/26/07
Hello again,
<<Hello Randy>>
Thanks for the advice given below.
<<Hope it was useful>>
I went ahead and got myself a slightly used Iwaki MD 100RLT from a fellow reefer to power the closed-loop (way too expensive to buy a new one).
<<A good choice and surprisingly quiet for their size/flow-rate... in my experience>>
I am about to upgrade to an Oceanic 72 RR bow front that has the mega-flow overflow and now some new dilemmas have arisen.
<<Oh?>>
Underneath I am going to be setting up a 10 gallon refugium that will be fed by a T coming from the tank drain w/ a valve to slow down the rate and then gravity flowing at a slower rate into a 10 gallon sump w/protein skimmer, etc.
<<Ok...but rather see use of larger vessels if possible>>
So now that you have an idea of the setup here are some questions that I hope you can help me with.
<<I shall try>>
1. Do you think that the Iwaki MD100rlt pump is too much pump to be used as the return line for my sump?
<<Gosh yes?!  The 1” drain in your “mega” overflow will only handle about 350gph before you start having issues...and it will certainly NEVER handle the output from a 2000gph pump like your Iwaki>>
I am torn between attaching my manifold to the return from the sump, or using a second pump as a return and keeping the manifold and Iwaki pump on a closed-loop.
<<The latter is your only choice here...with something like a Mag-5 for your sump-return pump>>
2. Considering that my manifold was made for a 55-gallon, three of the four sides fit perfect in the 72-gallon bow front, except obviously enough the bow side.
<<Yes, but is this really an issue?>>
I am contemplating getting some schedule 20 PVC and using a heat gun to bend the PVC into the curve needed to flow with the line of the bow and then cutting in where needed for the T's.
<<I see>>
Do you think that schedule 20 PVC will be strong enough to handle the pressures, and do you know if it is strong enough to be able to handle heating it up and bending it like I want to do?
<<Yes to the first (I can see Bob cringing)...<I am. Use flexible instead. RMF> I have used this pipe myself (has a larger inside diameter than SCH-40 of the same diameter, i.e. allows more water flow) with good/reliable results on straight unrestricted runs, but I don’t know that it has enough thickness for bending without becoming too weak/flimsy.  But it is cheap enough I think you should give it a try and determine for yourself...can always go with SCH-40 if need be.  Have you bent PVC before?  You will need to place some type of media “inside” the pipe when you go to bend it to keep the walls from collapsing...sand often works well and will also help to hold heat>>
3. In plumbing my refugium I am trying to figure out if I should have raw water from the tank flow into it, or skimmed water T'd off from the sump?
<<Raw water from the tank>>
Then depending on that, where I want the water going as it comes out of it; into the skimmer compartment or past it to be pumped up to the tank?
<<Directly to the pump chamber to prevent the skimmer from removing plankton is my choice>>
I figure it should flow past the skimmer to allow any living matter that escapes a chance to make it up to the tank and become food.
<<Ah yes...so you do understand>>
I am also thinking that is should be raw water flowing in because the waste from above can become food for whatever is living in the refugium.  Does my logic make sense?
<<You’ve already figured it out...yes, makes sense>>
Thanks in advance for your input,
Randy
<<Always welcome, Eric Russell>>