Please visit our Sponsors
More FAQs about Plumbing Closed-Loop Return Manifold Pump, Circulation Issues

Related Articles: Plumbing Return Manifolds, Plumbing Marine Systems, Refugiums,

Related FAQs: Closed Loop Recirculation 1, Closed Loop Recirculation 2, Closed Loop Recirculation 3, & FAQs on: Rationale, Designs, Plumbing, Troubleshooting/Repair, & Marine Plumbing 1, Marine Plumbing 2, Marine Plumbing 3, Marine Plumbing 4, Marine Plumbing 5, Marine Plumbing 6, Plumbing 7, Plumbing 8, Plumbing 9, Plumbing 11, Plumbing 12, Plumbing 13, Plumbing 14, Plumbing 15, Plumbing 16, Plumbing 17, Plumbing 18, Make Up Water Systems, Pumps, Plumbing, Circulation, Sumps, Refugiums, Marine Circulation 2, Gear Selection for Circulation, Pump Problems, Fish-Only Marine Set-ups, Fish-Only Marine Systems 2, FOWLR/Fish and Invertebrate Systems, Reef Systems, Coldwater Systems, Small Systems, Large Systems, Water Changes, Surge Devices,

By and large, the more circulation (non-linear) the better. UW scene... some Ascidians, hydrozoans, SPS... what have you. Wakatobi pix.

Closed loop... pb issue; cavitation from too large pump, too small pb     8/11/14
I have a closed loop on a drilled tank, bottom has 5 inch bulk heads, i drain
<Wish there were two>
and 4 returns, i have a Iwaki rated at 1900 gph , 1inch in/out. Out is plumbed to pvc manifold that has flex to the 4 returns. I also have union valves on inlet and outlet.
When i try and run wide open it cavitates and produces lots of bubbles, if i back down it is fine. Question , would increasing the pipe size on the inlet to 1.5 inches help?
<On the intake side; yes>
It would still have a 1inch bulkhead and pump inlet ( just between a larger pipe)
<... need to re-drill the tank... Enlarge the bulkhead as well. Bob Fenner>
re: Closed loop
<What I'd really do is to change the pump on your current arrangement to something smaller flow-wise (like by half), and instead provide circulation within the system... via pumps, even powerheads... See WWM. Closed loops are for the most part passé nowayears... for a few good reasons. BobF>
Re: Closed loop     8/13/14

If I back it off I do not get bubbles , I do have some streams in side tank Thx
<No sense spending the money on electricity to throttle-back, nor the added waste heat of a too-large pump. B>

Re: Question re. plumbing a closed loop manifold, pump pb 12/12/09
Thanks Scott for your quick response. One clarification, and subsequent question. It is in fact the Barracuda I am considering, but I got the G/hr wrong in my original e-mail. With an estimated 10 feet of head and at least 8 manifold openings at 350 G/hr per opening, I figure this kind of power is necessary.
<Will work fine.>
Anyway, these pumps come with a 1 Ã'½ inch intake instead of the 2 inch that comes with the Dart. In your comments below, did you recommend going to a 2 inch intake instead of the 1 Ã'½ inch because of the 2 inch intake on the Dart? Or is it a good idea to go with a 2 inch even though I will need to reduce it to a 1 Ã'½ inch anyway before it joins the pump.
<I would intake with a 2" line at this flow, just reduce it at the pump connection.>
In terms of my options, I think I'll try the over the tank one first, but move to drilling a new hole if it doesn't work out as well as I would like. I will, however, start to read with more interest the FAQ's re. tank draining/relocation. Regardless, option 2 is off the table.
Thanks again. Andrew
<Welcome, have fun, Scott V.>
Question re. plumbing a closed loop manifold
Ah, knew I should have waited. One additional quick question. If I stick with the 1 Ã'½ inch PVC vs. the 2 inch, but put one such "U" on either end of the tank and join them before it gets to the pump, will this sufficiently increase the flow capacity?
<In a similar way to using 2", yes. The 2" vs 1.5 is not life or death here though. The 2 is just "better", but the difference in flow will likely not even be noticeable to be honest.>
If I did that, would it be better that each "U" is separate or can they be at opposite ends of a common piece of PVC that spans the bottom of the tank?
<May be the way to go. I am a fan of multiple intakes when possible. Stuff always has a way of clogging up junk when you just have one!>
Let me know if I am not describing this well enough, and I will try my hand at PowerPoint again.
Thanks muchly. Andrew
<Welcome, Scott V.>

Pump?? Closed loop choices 4/15/09
Hi, crew of the W.W.M.
<Hello Manny.>
I'm planning on doing a closed loop on my reef tank.
I ordered a Oceans Motions 4 way.
The thing is I got two pumps one a mag-24 the other is a Gen-X PCX 100 water pump and I'd like to know which one would you suggest. I know the Dart would be the chose but, not at the moment. Here is a drawing of what I plan on doing. Any suggests would be grateful.
<It looks good, a plumbing and graphic masterpiece for sure! For the pump I would just use the GenX for the time being. It is just going to be the more reliable choice in this situation
from my experience.>
Again thanks for the help in the past it cleared up my mind.
Thanks Manny
<Welcome, have fun with this project! Scott V.>
Pump?? Closed loop choices 4/16/09
Thank you, Scott for the fast reply.
<Welcome, have fun, Scott V.>

Closed Loop Plumbing 2/4/09 Hello To all of the people who have inspired me to become a better fish keeper and now I am in the midst of a complete overhaul of my tank. <Great to hear, hello!> Onwards and upwards to the question at hand. I'm currently trying to plumb a closed loop using 2 pumps (what I have on hand) what would be the best route "t" together at the sump or can I have separate inputs on the closed loop? <Either can be done. You will just want to make sure the line is large enough as to not restrict the flow too much. What size pumps are we talking about?> I'm lost and would appreciate any input you would have. Robert McGee <Do also distinguish between a closed loop and sump returns. If these are feeding from you sump you will want to take a look at the overflows to be sure you have enough capacity there. Scott V.>

Pump size question 10/25/07 Hi. I am setting up a new 75 gallon reef. <Hello, congrats on the new setup> I drilled the tank for a 1.5" bulkhead for a drain, and plan to go over the rim for the return. Head height is about 4'. I am wondering what pump size I need for the return. I am planning on using 1.5" flexible PVC for my drain and return lines. I am going down to the sump and directly back up with only 1 return. I could T off and do 2 returns if it is recommended. <That depends on other flow in your tank. If you have powerheads or a closed loop, then one return should be fine. If that is your only planned tank flow then I would recommend two smaller returns. Either way, 1.5 return is not necessary, Ã'¾ or 1 will be plenty. > Am looking at a mag 9.5 which looks like it should be a great match, but I wanted to clarify. <Mag 9.5 is fine for your setup with one 1.5 overflow, although I must say I am a fan of overflow redundancy (if one 1.5 overflow will flow a Mag 9.5, then two 1.5 overflows provides a safety margin if an overflow gets clogged). It is not absolutely necessity, just something to consider. > Thanks! <Glad to help, Scott V>

Return Manifold and Pump Size? - 03/03/07 Hello to all and thanks in advance, <<Howdyand youre 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 (48l x 12w x 20h). <<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). <<Heeindeed!>> I am building the system out of Ã'¾ in. PVC tubing and fittings, and going down to Ã'½ in. at the 45 degree elbows coming out of the Ts. 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. <<Ahgood 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 Ã'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 timeotherwise 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 increasingahh 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-loopthough 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 youre 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 wont 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 dont want to make soup of my tank with super high temps, especially come summer time. <<Understood. Dont discount the effectiveness of evaporative coolinginstall 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 dont 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? <<Youve already figured it out...yes, makes sense>> Thanks in advance for your input, Randy <<Always welcome, Eric Russell>>

Manifold Questions 12/29/06 Dear Crew, <<Hello>> Your site is GREAT. <<A collective effortthank you>> Thank you for such an awesome resource and your time. <<We are happy to share>> I have some Q's re: setting up a manifold & related pump mechanics. <<Lets see if I can be of service>> I have a 135 gal. FOWLR w/ 1200-gph over-flow to sump and return to tank by 1100-gph external pump. I'd like to use a 2nd external pump (dont want the heat/look of a submersible) for the manifold if possible. <<Ok>> I am looking at a Sequence Reeflo "Dart" pump, rated @ 3,600 gph with only a 160 watt draw. I cant/won't drill the tank and dont really want a 2nd overflow. <<Well, that complicates things (though I dont recommend a siphon overflow for this application). How do you expect to feed this pump?>> 1) I assume I can't use Dart from existing sump/overflow because the Dart's rating will overflow my tank unless I add a lot more overflow capacity? <<Indeedand even so, if this sump is located in a living space you would likely find the noise from the extra volume to be quite disagreeable>> 2) Looking at the pic below, can I avoid an overflow box by just setting the Dart below the PVC siphon line in the tank. <<I wouldntthese pumps are not self-priming, and anytime the pump stops your prime is likely to be lost>> I assume siphon would be fine once pump is running? <<Till a power outageand how do you propose to start the siphon in the first place?>> But, would this set-up maintain siphon in event of a power loss? <<Is a gamble. If all the manifold outlets are submerged you might be able to maintain the siphon but there is no certainty. A gravity drain/below-water throughput is the only way to feed this pump in my opinion>> 3) If the pump is "self-priming", does this mean it draws the water from the tank and creates the siphon (or does the pump only push water that's already reached it)? <<Do double-check with the manufacturer, but Im pretty sure this pump is NOT self-priming and needs to be flooded to function properly>> 3) The pump has a 2" suction & a 1.5" discharge. I need to take the discharge down to 1/2" for the manifold. What effect will this have on the flow rate & the pump life? <<There will be some decrease in flow as the pump is not pressure ratednot aware/sure of effect on pump life, if any. This is a popular pump for this applicationperhaps you could post this question among the users of this pump on the reef forums (reefs.org/reefcentral.com)>> I assume it decreases flow rate, increases water pressure and decreases pump life? Is this ok? (both for purpose of manifold & pump)? <<Yes to the first twoand the increase in pressure is a desirable aspect for use with the manifold>> 4) If my planned set-up does not work for reasons you will explain, can you please suggest how I would set-up a manifold with my 1200 gph overflow or is my only option a submersible? <<Hook the manifold up to the return from your external sump pump>> If a submersible, can you please suggest one? <<As in in the tank? Perhaps one of the larger Mag-Drive pumps (24, 36)>> Any guess as to how much temperature would increase w/ a submersible? (I can't afford a chiller). <<Could be significant (4-6 degrees)>> 5) Any other help you can provide would be SO appreciated. <<You have two options as I see it Paul. Either drill the tank to feed the additional pumpor simply design/connect a manifold to be used with the existing sump return pump>> Thanks for your help, Paul <<I hope it has been useful. Regards Eric Russell>> Pump Recommendation ... for closed-loop 11/28/06 Hey Crew, <<Hello!>> Ok these are my last two questions for a bit, I promise!!! *Fingers crossed* <<No worries mate...is what we do>> I need a recommendation on what to do about my water flow pump on my 55-gallon tank. Right now I have a Mag 9.5 running my water flow within a closed-circuit. <<Closed-Loop?>> It works great. <<Ok>> The problem is that the pump is in the wet dry to prevent any problems due to dripping water. The pump is so loud and causes so much vibration that I can hardly be in the same room, not to mention the fish stress that I am sure the vibrations are going to cause. <<Hmm...strange. I utilize a Mag 12 for my return pump...and it is pretty quiet. Based on your previous comment Im guessing your pump is hard-plumbed? Perhaps using a short length of soft tubing at each pump connection, and setting the pump itself on something cushy (a mouse pad) will alleviate much of the vibration and noise>> Any recommendations on an exterior pump that is much quieter? <<Iwaki pumps are extremely quiet in my experience (Japanese motors), but its hard to beat a good submersible installation>> Any recommendations on how to quiet this pump down? <<As already stated>> The noise is coming from three things; a) the pump rests against the plastic of the wet dry and it acts like a drum. <<Indeed...hence the need to isolate/insulate the pump re with a cushiony material>> a) There is really very little room to correct this due to the size of the pump and the PVC coming out of it but I was thinking about wrapping the PVC in insulation to create a cushion. <<Now youre getting it>> b) The pump is suspended in mid-air resting on some spare PVC so as not to affect the water level or the pump in the wet dry. <<Mmm...then perhaps you can wrap the pump with mouse pads or similar material (secured with nylon zip-ties)>> c) The pump makes a clicking noise like a power head that is out of water. I am thinking that I never noticed this noise before because I have never heard the pump operate outside of water. <<Might want to check/replace the impeller>> 2) I am running a wet dry that uses a Cap 1800 to pump water in to a 10 gallon fuge. The fuge then uses a Cap 1800 to pump water up 5 feet to the tank. <<This is not a good idea/configuration...balancing the two pumps to preclude an overflow is nigh on impossible>> Since one Cap 1800 is losing flow due to having to push water up. I am having trouble controlling the flow of water from the wet dry that is really not losing much water flow pumping up 18 inches to the fuge. <<My point exactly...much better to drill/plumb the wet/dry to drain via gravity in to the fuge...using a single pump for the return from the refugium>> The pumps come with a CHEAP ball valve to "control" water flow but it does not seem to want to stay in one place and finding the perfect balance as to where it should be set has taken me 48 hours and counting. <<The best valve in the world wont save you from eventual calamity...do rethink this strategy>> The lines on the pumps are 1/2" (interior diameter) plastic tubes. Any ideas on how to fine tune adjustments to water flow? <<Cant be done...reliably>> If set too high, the wet dry will run DRY and that is not good on the pump. If set too low, the wet dry is going to turn into a 10 gallon FULL wet dry which only hold 8 gallons. (Do the math 8 gallons - 10 Gallons = 2 Gallons on the floor + me sleeping outside to hide from my wife! "Honey, YOUR dog must have peed on the carpet A LOT. Don't worry honey, I will clean it up for you!! Bad puppy!") <<Hee-hee...indeed! Reconfigure the plumbing to gravity drain the one vessel in to the other or set up each with its own drain and pump...but dont use your current configuration>> Any help from these two problems would be great. <<Am trying>> I asked my LFS but they suggested a few auto shut off systems to control each pump and cycle them on and off when the flow got too high. <<(sigh) Thats ridiculous...and Im sure they would have been happy to sell them to you...>> Expensive solution in my book and not too good on the pumps I assume. <<A stupid and impractical recommendation...in my opinion. Are you certain they understood the situation?>> My local Home Depot was not much help and I know Bob Fenner has his honorary orange vest from there so I assume he might know a bit more then most of the people at the store! <<No argument there...but rest assured that my recommendations are good/in your best interest. Please let me know if you need/wish to discuss either option further>> Thanks in advance! Brandon <<Happy to share. EricR>>
Re: Closed-Loop Confusion (Maybe Just Me...ER) 11/28/06
Eric, <<Brandon>> To clarify for you. I have a wet-dry and a fuge, two separate things. <<Ok>> The wet-dry is just used to house carbon and other media with no bio-balls and the fuge is 10 gallons with a 4" DSB that is going to be used to house a cleaning crew and macro algae. <<Excellent...though I would be cautious with the choice of cleaning crew as many (crabs primarily) will prey upon the organisms you want to propagate in the refugium>> I wrote you another e-email but forgot to clarify the points in this one. In that e-mail I explained the wet-dry and the fuge are run with Cap 1800's and I am having some problems with that plumbing as well. <<Ah yes...I just replied to that query (and forgot to add a title/date...sorry Bob!)>> <No worries... add these everyday... B> The Mag 9.5 is ONLY for water movement. <<I understand...now <grin> >> Thanks for your recommendations. <<Always happy to share an opinion or two>> Will three outlets be enough to create water flow and future coral keeping? <<Quite probable...if the flow is strong enough to reach end-to-end of the tank>> From what you say, looks like if I want to run 5 outlets I need a 1,250 to 1,500 GPH pump. <<Yes...and still only use Ã'½ nozzles>> Can you make any recommendations of a QUIET pump able to produce this much flow? <<Iwaki and GRI make quality pressure-rated pumps that work well for closed-loop systems and are also very quite (considering). You will know they are there if out in the open, but based on your other email, I think they would be a more quiet solution than what you have (with the current configuration)>> Thanks for all your help, Brandon <<Quite welcome. Eric Russell>>

Equipment list for 500 gallon system 11/26/07 Hello, <Hey Kirk, JustinN with you this fine evening> And thank you for answering my question: <No problems, is what we exist (as a group of like-minded individuals, not as a personal crusade! *grin*) for> For my Xmas present this year, my wife has given me the OK to get a 450 (96x36x30) custom acrylic gallon tank for our new home. <Very nice! Quite an undertaking, and quite a woman for letting it happen. *grin*> The largest tank I have had to this point has been a 125gallon tank. I have been in the saltwater hobby for 8 years, but I must say this is an exciting but seemly overwhelming task. <Can be daunting> I know the choice of filtration, pumps, skimmers and crucial to the success of this project. <Absolutely> With that said, I would like to know what types of skimmers would you recommend for a tank of this size. I am going to have a mixture of fish (large angelfish, triggers (pink tail or bluethroat), butterfly (copperband), clowns, and possible a Naso tang) and corals (mostly being LFS and a clam or 2). I am NOT going to keep SPS corals. <Am sure you know this, but still feel I must mention that both the angels and the butterfly run a very high possibility of nipping both corals and clams to death.> Skimmers ------------ The research I have done so far has led me to the following skimmers: H&S Bubble King Deltec Klaes I would like to know if a Euroreef or ASM skimmers are a good choice for this large of a tank. Whatever skimmer I decide on, it needs to be a well design skimmer AND produces a sufficient amount of skimmate. <I believe any of these would be sufficient. Just to be safe, get a skimmer that is recommended for a tank larger than your overall water volume. That should give you the piece of mind you seek, regardless of manufacturer.> Filtration/Pumps ------------------- I am planning on a closed loop system, and for a pump choice it must be quiet and emit low heat. I was thinking about Dolphin AMP Master pumps, but some other reefers have mentioned larger Bluelines, but I do not know much about them. Can you offer any suggestions in this area? How much water flow (i.e., gph/hr) should I plan for?? <Alas, I have no experience with either pump, but going on what I've heard, I hear nothing but glowing praise for the Blueline line of pumps. Sequence pumps also seem to carry a similar reputation. Sorry I'm not of more assistance here.> Calcium Reactor ------------------ Is this a mandatory piece of equipment with a tank this size? If so, can you suggest some models for me to research. <I would not consider it mandatory, no, but it will simplify and automate that much more of your maintenance. Korallin, Knop and Tunze all make readily available calcium reactors.> Thanks for any advice you can give. Kirk <Well, wish I could say I had more specific recommendations for you, here, but I think you will do fine. Just read as much reviews of equipment as possible on online forums, talk to local reef clubs, and research before you purchase. Do keep us informed on this wonderful sounding project! -JustinN>

Re: Closed Loop Manifold! - 12/14/2005 Josh! Thanks for all the help. Also everyone on WWM for their support. <We're always happy to help!> I'm halfway in the process of building the CLM with no more questions thanks to your quick reply's and advice. <Glad it's clearer for you. Now you're obligated to explain it to someone else (that's the beauty of this:)> I only have to make a decision on the pumps to buy & use. <There's that word again..."pumps".> I Do like the MD7 pump I have, but really haven't tried any other pump, except for 2 Rios and I swore not to ever go back with Rio pumps again so, maybe I will buy one MD 12 or MD 18 or even MD 24 for the filtration cycle 24/7, and I will probably be going with the Sequence Dart for the CLM and have it on a timer. Does this sound like a descent setup for my 75g. <I agree with the Rio decision, but still don't under stand the desire for separation between filtration and CLM. Why not run both 24/7? Works just fine for me. Unless you're putting an extra drain in, I wouldn't go bigger than the MD18. You'll have to throttle the pump back too much (creates heat and wastes electricity, bad for pump life). I think Gen-X, Blueline and Iwaki are pretty much the same pumps...Tell me what you think...And let me know if I should go with the latter brands. Thanks... <They're similar designs sure, but some Rios look like Maxi-Jets too (which would you prefer). They have pro's and con's as most things, Iwaki I believe ranks at the top. Research these and consult forums as I've not used any personally (holding out on the big bucks for a dream tank). Still don't get the multiple pump idea... - Josh> Closed loop 125 - 1/30/2006 Hello crew and thanks for such a great site. I have just finished a closed loop system using a RIO 2500 with 3/4 Inch PVC. Very easy to do by the way and way cheaper than buying power heads. <Yes> Please tell Anthony he rocks. <Will do> Anyway this is a huge increase in flow to this system. Most of the corals are happy about it and the rest I suspect will adapt. The only ones that concern me are a colt and a long tentacled plate. The plate is on the sand and the colt in on a piece of LR near the bottom. The plate I could move if need be but the colt is a rather large piece and if firmly attached to a huge piece of LR. The water is not directly blasting them but it is a good deal more than they are used to. Just wanted to know what your thoughts on this may be. <Posted> Also want to thank you guys for the great help with my refugium and DSB. Both must be working because my Nitrates are below 5 ppm (Salifert) from a high of 25 a month ago. May have been higher then that as I only found out due to a false Red Sea test kit. Anyway my tank has been doing great since I have be reading WWM Thanks again 125 gal reef 225lbs LR Aqua C skimmer All water tests check ok Ca 390 Alk 10.4 Mg 1212.5 Ph 8.3 <Sounds, looks good. Bob Fenner> Thanks again you guys rock

Closed-Loop Manifold/Outlets/Pump Size - 01/18/06 I have been researching closed loop systems and the one on your website is by far the best one I've found. <<Tis some good info I agree.>> I searched through your site and couldn't find the info I needed so I'm hoping you can help. <<I will try.>> My tank is 36"L x 12"W x 21"H, well it's actually about 16 and a half inches at it's widest. I was wanting to put 6 to 8 tees in the manifold, but was wondering how many gph I should be trying to get out of each tee, and what size and brand of pump you would recommend. Thank you for your help! <<Assuming the tees are 1/2" you would want to shoot for around 350 gallons per hour per tee to achieve effective/useful flow/velocity. Limiting the outlets to six, a Mag-Drive24 submersible pump (installed with a gate valve on the outflow to temper flow if need be) should serve well here. Regards, EricR>>

Closed Loop Confusion - 02/11/06 Hi crew, <<Hi Linda>> I tried to send this email before but was getting error messages. I have not gotten a reply yet so I thought I'd resend my question. My apologies if you have already received it! <<Mmm nope, don't believe we did.>> I recently asked Bob a question regarding a closed circ system. I was having noise problems from my pump and design. <<A common issue.>> I had an intake (1" PVC) go up and over the tank, but had a tee on the top with a cap (so I could clean the tube easily). Bob suggested getting rid of the tee in the intake PVC and try a smaller pump. <<Okey Dokey>> So I've been researching WWM for pump selection and came across several posts regarding closed-loop systems (I didn't know it had a name before :). <<Hee!>> Now I am confused! <<Ruh roh>> Many answers said to NEVER use an over-the-tank intake siphon (which is what I assume my design is). <<Does sound like, yes.>> However, Bob didn't seem concerned about my design, and other posts suggest using one. Drilling isn't an option and I'm doing this because of heat issues with the power heads so I wanted to use an external pump. <<I see>> So, two questions (okay, three): Should I use my planned intake? <<Sure>> Are there any better options? <<From what you just told me...doesn't seem to be.>> I want to get an Iwaki pump - what size would work best? (I know you get this question a lot, but I still am at a loss) <<A good choice (Iwaki)... But how much water do you need/want to move? How much "head" will you have to overcome? Shoot for something that will give you a minimum of 10x the tank's volume. But you'll also have to consider the design of your loop (angles, number/size of your outlets).>> FYI - my original plan was a 1" intake going up over tank and down to a 1" on the pump. Return is 1" flexible tubing into a 3/4" PVC "network" of 3 tees up the back of tank with 2 lock-line nozzles on each (6 nozzles total). (I already had the network). <<Are these 3/4" nozzles? I'll assume so for now. Okay...you will need a pump that will give you 550-650 gph PER NOZZLE after calculating head loss. This may sound like a lot, but you need this kind of volume to ensure adequate "water velocity" from each nozzle. When calculating head-loss, add a "foot" for each 90 degree angle and for each 'T'. So, for example...six 3/4" nozzles would mean a pump that will produce 3300-3900 gph AFTER head loss. If you need/want this kind of flow your looking at something like one of the 'Sequence' pumps (Barracuda, Hammerhead). If you don't need/want that much flow, you can bush down the outlets to 1/2", this would reduce flow requirements per nozzle to about 350 gph, meaning a pump that will give you 2100 gph or so after head loss. Obviously, you can downsize the pump still more if you cap-off some of the nozzles. Whichever way you go, my suggestion would be to "oversize" the pump a bit (10%-20%) and install a gate-valve on the output side to temper flow "if" necessary. Thanks in advance, Linda Braly <<Hope you find this helpful...Regards, EricR>>

Return manifold 3/11/06 Hello Bob and the WWM Crew, I like to thank you again for all the expert advice. Been doing quite a bit of research on your site and have learned something new every time. Tons of information, and plenty of new ideas. <<Adam Here today. Glad you have benefited!!>> Please find attached a drawing for (2) return manifolds I plan on installing in my 150 gallon salt tank. I am using (2) because the center brace (1 of 3 braces) is wider than the tank edging and sits below the water level, this is the only way I can think of to install the units without constructing them inside the operating tank. <<This is fine... creativity is great! I am concerned that the brace sits below the water level, though. It sounds like the water level might be too high.>> Each unit will be powered by its own mag 18 pump located in my 55 gallon sump/ refugium below the tank. The riser pipe with a 5' head will be 1" pvc, connected to the pump via a short section of vinyl tubing, a true union ball valve will be installed for flow adjustment and as a quick shut off in case of a emergency. <<All sounds good, but glue and threads are safer than flex tubing and hose clamps if possible.>> At the top of the tank (2) 1" pvc-45 degree elbows with a spacer in between, will bring the feed pipe over the lip of the tank to a 1" fpt x fpt tee, from there the pvc will be reduced down to 1/2" pvc by a 1"mpt x 1/2 spt reducer, from there 1/2" pvc pipe will connect to the tees and jets, 5 total in each manifold. If I figured this right, my total loss is 9.84 feet of head or 4.25 psi, with a flow rate of 847gph for each manifold. Ok time for the questions, 1. Is this enough gph per manifold, or should I go to a mag 24 pump? <<I am already concerned about your drains or overflow handling two mag 18's. Your flow of about 190gph per nozzle (847/5) may be a bit low. You might consider going down to four nozzles.>> 2. Will the flatten 1/2" nipple work or should I look into something else? <<Should work great!!>> Any suggestions or comments will be greatly appreciated, Thanks again, Mark <<My only other suggestion is to be sure that your drains can handle the flow of the pumps you are planning on using. Best Regards. AdamC.>

Some Closed-Loop Methodology - 07/26/05 Hello crew and thank you for the support that you guys <<and gals>> give to the less experience people. <<Is truly our pleasure to help>> Let me start by saying that the tank is not set up yet, haven't run for 2 Years after a few hurricanes here in Florida wiped my whole stock. Yes it has taken me some time, he-he, but yes I do miss it ). <<Welcome back>> Ok, I have an All-Glass 75 gallon that comes standard 1" drain and 3/4" return. <<Mmm...indeed...>> I modified it to have a return line of 1" and 1 1/2" drain for more flow. <<Yay!>> Also I made a closed-loop manifold 3/4" pipe with 6- 3/4" nozzles with possibly two more that are capped now. Want to know what size pump I can use for return and what for closed loop. I had a Mag-7 running for return which my LFS sold me, but I still think is low for a semi-reef tank. <<The Mag-7 is plenty big to serve as a return pump here, but if you want more flow from your return and the increase in noise, bubbles, etc is not an issue, then a Mag-12 should work without overcoming your 1.5" drain. But plumb a gate-valve on the output side of the pump to allow for some adjustment as/if necessary. For the closed-loop pump, figure about 600-700 gph per nozzle to provide sufficient volume/velocity from each of the 3/4" nozzles. That means for your current configuration you need a pump that will push (after figuring head) about 4,200 gph...more if you plan to uncap the other two nozzles...and is a BUNCH of (too much?) flow for a 75g tank>> This time I'm going stronger, better lighting, better flow and better stock. Hard and soft corals and a some exotic fish. I plan or would like to run a main pump running 24/7 for filtration and another one only a few hours a day for closed-loop circulation on a timer with a random setup. This will give a calm time for like feeding and some days more current. <<Do be sure you are still providing adequate flow when the loop is "off">> But I also know that some corals like all time flow or current. <<Indeed...even "require" it>> My big question is? Should I use only one pump for everything and plumb and use the manifold of the closed-loop also as my return or is my presented plan setup better. <<Okay, couple things to mention here...1) If you use the closed-loop for your return then technically it is no longer a "closed-loop". A closed-loop system is one that is plumbed as a "closed" or sealed unit directly from the tank to the pump and back, i.e.- no sump. This allows the user to utilize high-flow pumps with pipe diameters much smaller than those required to handle the same water flow through a gravity drain...which brings us to the next issue. 2) If you use the "loop" as a return manifold, there is NO WAY your 1.5" drain will handle the 4000+ gph needed to effectively drive six 3/4" nozzles to vigorous flow rates. So my friend, to truly implement a closed-loop you will need separate pumps for your return and the loop>> Any exterior pump recommended? <<Lots of folks use the "Sequence" brand pumps high flow closed-loop applications>> The size for each one if two. <<Have already stated>> Or just one more powerful. <<Not if you want a true closed-loop>> There will be between 4-6 ft of head for the filtration and if going with two pumps, only about 2 ft of head for the closed-loop. I was thinking of Dolphin pumps, very quiet and energy efficient, but don't know what size. <<Probably in the 5,000 gph range for the closed-loop...but this is an awful lot of flow for this tank. An option would be to bush down the nozzles to 1/2"...could go with a pump flow rate of about half this or less (300-350 gph per 1/2" nozzle) and still get sufficient velocity for good water movement, or simply reduce the "number" of nozzles>> Other quality good brands are welcome...And thanks for taking the time to advise all of us... Pedro Velasquez <<Happy to assist, and do let me know if I have not been clear here. Eric Russell>> Re: Some Closed-Loop Methodology - 07/27/06 Hello again, and thanks for the quick response Eric. <<Quite welcome>> I did have in mind that it wasn't going to be a closed-loop anymore if I plumb the manifold with the return line and use only one pump. <<Ah, good>> But I also forgot to mention, that if I go this way, then I can use the 1" return to be also a drain, and have two drains, one 1 1/2" and the other 1" to handle more gph. <<Indeed this is so, but still only a maximum capacity of about 1300-1400 gph. Not near enough to effectively drive six 3/4" nozzles to sufficient velocity to provide vigorous water movement>> But maybe this is more complicated adjusting the two drains than just a main return pump and a second pump for the closed-loop. <<Not so much complicated as I think separate pumps are more efficient for the tasks at hand>> I guess I could reduce the nozzles to 1/2" and use a smaller pump, maybe a 3600 gph. Does that sound much better. <<Still larger than you would need...but can be attenuated with a gate-valve plumbed in-line to the tank>> And again do you think the MAG-7 is capable of handling the flow of 1.5' drain. <<Not an issue...the drain can only "drain" as much water as the pump "pumps" to it...up to the capacity of the drain, of course>> Would only turn it less than 10x. <<This is where the closed-loop comes to play>> I would like to turn the water as much as possible. <<Is not necessary, and usually not even desirable, to push all the tank flow through the sump>> I like Mag-Drive pumps, but want to go external (less heat), any more recommendation is appreciated. Thank you. <<Iwaki and Gorman-Rupp are both excellent "external" pumps. You should be able to find a model(s) to suit. EricR>>

Re: Closed-Loop Pump - 07/28/06 Thank you Eric. <<Quite welcome Pedro>> The question are gone for now, but I'm sure they will come as soon as I start to build the system. Pedro Velasquez <<Indeed my friend, do let me know if/when I can be of further assistance. Regards, Eric Russell>>

Another closed loop question 9/26/06 Hi All <Robert> I've been reading all your info on closed loop manifolds and want your input on what I need to power this thing. At this point I only have a Iwaki 40RLXT running my sump and it's rated at around 1100 gph.. If I need a 20X per hour circulation, then my 157 gal tank needs around 3600 gph. Will it be possible to get a manifold to handle the 2500 gph I'll need? <Yes...> If so what pump would you recommend or do you have another suggestion on how to get the water movement I need. Thanks Robert <Posted... see WWM re. BobF>

Closed Loop Pump - 10/15/06 I am wanting to add a closed loop to my 120 gallon reef tank to get rid of my power heads and I was wondering what size pump would I need to use for this. <??? Too many pumps and possibilities to answer this question. Time to start doing some math with plumbing and see which pump will do the job for you.> I am only using a 600 gallon per hour pump for my main circulation so my flow through my refugium isn't chaotic and to stop micro bubbles. So I need more power I was thinking about using a mag drive 24 that pumps out about 2400 gallons an hour is this to much. <Sure, why not?> I am just going to be keeping softies and LPS. Thanks. <Cheers, J -- >

Closed loop... alternative to powerheads, heat production 11/8/06 Greetings from Canada... A couple of quick questions.... 1-a closed loop of 6' long x1' wide powered by an 1800g/hr mag drive pump. How many outlets (minimum/maximum) can it handle to deliver adequate flow through 1/2" CPVC? It's a 125 gallon tank...72"x18"x24".. <Mmm... six to eight is about maximum/ideal here> The loop will be hung from the cross members in the centre of the tank as it's impossible for me to run it along the perimeter or build a sump. 2-The pump is going to be hung inside of the tank. Will it cause heat issues? <Will contribute to 1/2mVsquared here to an extent, yes> I currently run 8 powerheads <! Time to look into fewer, more powerful? Perhaps a "Tunze" Christmas this year?> so will there be much heat difference as I will obviously be removing the powerheads have appr 120 liverock 5" oolite aragonite sandbed and a remora pro skimmer. Thanks for your time and response...Pete <Only real time, experience can/will tell here... Mag pumps run hot... I suspect hotter than your collective powerhead assemblage currently. Bob Fenner>

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

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

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

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

Return Manifold pump selection 7/7/05 I love this resource you guys have and thank you very much for the wealth of information. I'm building a new 120 gal. FOWLR acrylic aquarium for my shop and since I'm having it built I want to do it the right way first. I may eventually put inverts and easy hardy corals in later so I'm trying to plan for it now. I've been reading up as much as I can in Anthony's book "Book of Coral Propagation" (great book) and am awaiting my copy of the "Reef Invertebrates" book. I'm currently picking out my equipment and deciding how I'm going to do the plumbing for a 120 gal acrylic tank. I would like to incorporate the "Shelf overflow" idea that is in the Book of Coral Propagation" (illus. on pg.42). <Mmm, please read (and read!) here: http://www.wetwebmedia.com/pbh2oret.htm and the linked files at top/s... Bob Fenner>

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

Closed Loop Manifold - 12/11/2005 Hello guys from WWM! <Hi there Pedro! You've got Josh again.> Do you think it will make a lot of difference in flow if I make the return line for a 75g which is 3/4" to 1" to the top or beginning of the loop, then tee off for 3/4" pipe for the loop and outputs or just don't even bother of drilling the hole bigger for a 1" bulkhead and just do the 3/4" pipe all around. <I would just stick with the 3/4" all the way. Going from 1" into the tank and then dropping to 3/4" isn't going to be helpful.> Does the CLM need to be separate from the filtration cycle? <Nope. Just make it the return from your sump.> I don't have anything setup yet, I'm in the planning mode. I don't have a pump for this right now, but will like to have a descent flow. <I thought you had the Mag 7.> Any recommendation will be appreciated. Need advice ( size and Brand )on an external pump that can be use as a return pump for main display and another for the Closed Loop Manifold. <You're fine with the Mag Drives, and the good news is you only need/want one pump to return water to the tank via your closed loop. Running two will be a problem as no two pumps will ever match each other precisely (you'd basically have to set up a sump per pump). Just size up to perhaps the MD12 or MD18 and control the output with a ball valve and more outlets.> I have a Mag 7, which the LFS sold me, but now I understand that's not enough. <If you're not running it yet, why not return it toward a bigger pump?> What can I use that mag 7 for? Is it too much to use on a skimmer? <Depends on the skimmer really. Find one that operates best with at least 700 gph and I don't see why not. Personally, I always have some crazy scheme for spare pumps. Cheapest route would be to try and take it back for a credit.> Thank you WWM. Pedro Velasquez. <Sure thing Padre...uh Pedro>

Manifold flow questions 4/20/04 tank is 75 gal tall set up as reef tank. it has 1 800gph pump on a closed loop behind live rock, <do be careful that the pump is accessible/serviceable> (tall tank is not very deep from front to back so rocks are touching the back wall). <this is a habit to be avoided with strategic rockscaping (stitching, shelves, arches, etc> overflow has been enlarged slightly to 1 1/2 in and the return pump is a velocity t4 returning to tank thru a thing called a "SQUID" which diverts the flow between 2 - 3/4 inch returns that each have 2 - 1/2 inch lock line nozzles. No other circulation pumps. The flow is "OK" but not as good as I would like. <agreed... this is only about 10X and the most successful reef tanks have closer to 20 X. Paletta cites some of the best in the world as having upwards of 40X water flow (SPS tanks)> I read the articles about the manifold around the top edge of the tank with 6 or so outlets and the 45 degree fittings used as nozzles and it sounds like it should work. except that many on you site warn against "laminar flow" would I not just have 6 small "laminar flow" problems with the manifold? <no my friend... multiple swiveling, adjustable and converging outlets produce random turbulent flow (ideal). The flow coming out of your unaltered return pump or any given powerhead is simply laminar flow> With 6 outlets running all the time the flow would be reduced quite a bit but it still would be in a fixed direction, is this acceptable and would the water flow be improved enough to be worth the effort. <yes, a tremendous improvement> also what do you think of the "SQUID" things , it does what it says but I think it reduces the flow quite a bit. <they are quite nice> thanks for any comments. Carson Crenshaw <best regards, Anthony>

- Two Pumps, One Pipe - Hello all, Quick question for ya. Is it possible to run two pumps on the same closed system return manifold (and two separate intakes)? <It is possible, yes.> Is there a special valve that I would need in order to prevent troubles if one pump failed? <I have a better question... how would the 'valve' know a pump had failed? You can put check valves on each pump, would prevent one pump from flowing into the other.> I currently have a 90 gallon reef with two Hagen 802 power heads and an Eheim 1260 return producing the only current. As I have done more reading on your site I have come to realize that this is not sufficient circulation. <More would be better, yes.> I would also like to get the power heads out of the tank due to heat concerns and therefore am planning on building a water return manifold. I would like to use two Gen-x pumps because it would give me some security in case one pump fails and because it looks like they would produce more circulation at fewer watts than any single larger pump would. <Why not split the manifold in half... half a manifold for each pump.> I hope I included all the info you need. You are all doing an awesome job and I'm sure there are literally millions of captive marine animals all over the world that have benefited from your advise. Thanks. - Chad Calgary, Canada. <Cheers, J -- >

Water flow closed loop manifold 10/31/04 Hi guys/gals, <howdy> I have another question pending, but here's a new one. I just installed and ran my closed loop (to replace powerheads) in my 90 gal reef. The pump is a mag-drive 1800 gph running out of 7 outlets in the tank. Some of outlets have decent flow- some barely any. <the manifold is under driven here... tis the problem. even if you get the full 1800 gph without any head/resistance (not happening), that only gives you a little over 200 gph per outlet... that is staggeringly low by even tiny powerhead scale. More flow or less nozzles (hopefully not) will do the trick here> I'm now thinking of splitting the loop into 2 loops, and adding another pump. Is this too much flow? <the latter is the way to go... and no, my friend... you are not even remotely approaching what these animals get on the reef> Will the tiny bubbles jetting out soon disappear? <don't know... with no info, I cannot say where they are coming from. Do a keyword search of our archives for "air bubbles" and see many explanations and solutions. If you don't actually have air in the sump visibly being aspirated by the pump... then you may have a pinhole leak in your manifold somewhere> I want to create random turbulence, but my dog can drool faster than some of the current outlets. <the pump is sized too small my friend... no need to complicate/double the loop> Any pointers would be appreciated. <where slippers around your dog> Thank you James P <kindly, Anthony :)>

Closed loop system I am in the process of building a 1" PVC loop with ¼ tees that have 90 degree swivels(10 of these) that will mount on top of my 180 gallon reef tank. I plan on using a external pump some where in the 2000 gph range with a ball valve to control flow (any suggestions on type?). <Iwasaki's are popular> This pump will need to take the water directly from the main tank since my overflows are all ready maxed and the return from the sump is pumped back into main display. I would like to hide the intake that will be used to draw the water for the external pump (also protect my livestock from the intake). Would it be possible in your opinion to place the intake in one of the overflow boxes? <Ideal as long as the box itself can handle the flow.> Or would the water be pulled out faster than it would be replaced. <Depends on flow *now* and how big the box is, what it's designed for.> My other thought is to some how build a protective box around the intake and hide it with rock? Your thoughts and opinions are always helpful and are appreciated. <You could do that or perhaps split the intake between two overflow boxes? Complicates plumbing a bit, but might be better for box capacity. The other choice is larger overflows....not much help, huh?> Thanks, Mike Winston <Hope this is useful! Craig>

Closed loop flow rate I posted a similar question on the chat forum and the responses spawned a new question. I wanted to know how much head pressure loss I have with my current closed loop wave-making system with a SQWD and the best advice anyone could give was that each 90-degree elbow adds about 1 foot of head pressure. This information is consistent with the ReefCentral calculator, <It isn't. Just go to RC and enter the params.> but if this is accurate I should be getting no flow out of my SQWD at all. <Yep, it assumes you are getting the right info from the chat....best to just go to RC. In your case, friction factor/pipe size, horizontal length, number of ells.> With 1 foot of head pressure, 5 elbows and 1 SQWD that's 7 feet of head pressure. According to the manufacturers specs I should be getting no flow out of my CAP2200 at that amount of head (says N/A). Do you know what these calculations are based on? Are they "calculations" or are they anecdotal? <No, they are real, but you can't assume one part of a complex equation and make it a simple calculation.> Needless to say, I am getting flow out of the returns... not as much as directly out of the pump, but seems to be at least as much as a powerhead... may upgrade anyway though. Jeremy <Of course! Best to engineer a system to move the volume of water you need, than to just upgrade pump. Plumbing size may be a factor as well. Better to look at all the parts.... Craig>

Return Pumps and manifold 7/1/03 Hiya, <howdy> I was talking to Anthony the other day about making a spray bar for my 80 gln reef. He suggested I put in a bigger pump and basically an adjustable spray bar for the return coming from my sump. this would eliminate some power heads and heat from my system and greatly improve circulation. <correcto> I was thinking of using one of the new Tunze wave maker pumps to do this. The general consensus is this will not work, (you can't use a wave maker for your return is all I hear) with nothing substantial to back up the argument. <actually... the Tunze streamer does not need to be harnessed to a manifold... quite competent in its own right> I can not see a reason why it wouldn't. <no need> What I can see is maybe the pump would have a load that it wasn't designed for which in turn will shorten it's life span. My system is low tech and all my skimmer really does is oxygenate my water. So having a surge through my in tank sump won't bother much. These are pricey pumps, and it will take some creative work to connect to any kind of plumbing, so I want as much input as I can get before I go shell out $300 to get one. Thank You Steve <the Tunze models are really outstanding and turnkey... the closed loop manifold we chatted about at DMS is rather a DIY project for a large return pump from the sump> P.S. Tell Bob and Anthony the DMS says thank you for the awesome evening. <we had a great time and met really nice folks like yourself! A blast. Kind regards, Anthony>

Getting Looped! Thanks for the reply Scott F., (my name as well, with out the F!), Would you run the entire system on the Mag 12, or would you run the "loop" independently, both pumping from the sump? <Well, in a perfect world, I'd run the closed loop right from the tank, rather than from the sump. It would be independent from your main filtration/circulation system> For better savings on the electric bill, I'm thinking that running the entire PVC maze from the Mag 12 makes more, (saves more), sense to me! <Well, in the long run- cost is an important factor- so you'll need to be the judge of what works best...If you elect to use the system pump to run the whole thing- that's the way it will be! Good luck!> Thanks again Scott F. at WWM, from me, Scott B. in Denver! <A pleasure, Scott! There are so many ways to accomplish the same thing, so do what feels right to you! Regards, Scott F. >

Many Manifold Questions... Dear Crew, <Scott F. your Crew member today> Reading through your plumbing articles and FAQs has inspired me to redo my reef plumbing. I especially love the closed loop manifold and am thinking I need to mosey on down to the local hardware store to start picking up some PVC. <Great idea, fun to plan and build, and really useful!> I have a couple of questions before I mosey, though. <Sure..> I have an in-sump Mag 9.5 whose return line is upgraded to a 1" flex hose. The return line travels five feet to the top of the tank and will connect to a 3/4" pvc closed loop manifold. Question one: Wouldn't 8-45 degree angles in each corner rather than four 90 degree angles help to prevent the water return pressure from reducing in the manifold? <Good question, and I suppose the answer really depends on the outlets' distance from the pump. On the other hand, you want a fairly sizeable number of outlets for maximum water dispersion/circulation, so it may be better to go with the greater number of outlets at lower pressure...You may have to experiment a bit before the manifold is installed...> Question two: I plan on having six outlet Tee's, one in each corner between the 45 degree angles, one in the center of each long side. The tank is 36"LX18"X18". What I haven't been able to determine searching through the plumbing/manifold FAQs is what size should the flexi ball socket tubing for the outlets be, 3/4" or 1/2". I'd like to get the best flow possible coming out of the outlets-not too weak, not too restricted. <Agreed...If it were me, I'd go for the 3/4"> Thanks again for all the help you folks have given me and fellow aquarists. Chris <Always a pleasure! Good luck and have fun! Regards, Scott F>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: