CircMarFAQ4

FAQs about Circulation in Marine Systems 4

Circulation can provide exercise for your motile livestock.

Playing With Sand And Moving Water! Hi guys, <Scott F. your guy today!> I have a live sand question. Talking to the rep from Pure Caribbean and he had mentioned seeding my DSB with 10% of total percentage of tank substrate with a live sand. <Good idea, IMO> My question is this. He said, "do not get that bagged/packaged stuff", make sure it is good quality." What does this exactly mean? I have never dealt w/ live sand and not sure where you get good sand from. The online merchants I looked at never did tell how it came (Premium Aquatics, Marine Depot etc...). <Well, I think what the rep was referring to is the so-called "live" sand that comes in the bags. These products are essentially inert sand enriched with a bacterial solution. Live, yes- but not filled with a diversity of life that you want from "true" live sand. Many etailers offer "live sand" that has been collected from, say, Fiji, or cultured in their own facilities. Most of these places offer sand that has a variety of worms and other desirable life residing in the sand. Alternatively, you can use "dead" sand, and get a "starter kit" from a place like Indo Pacific Sea Farms (my personal favorite) containing some of the desired infauna to "kick start" the sandbed.> Quick question about pvc plumbing. I believe the Dolphin Amp master web site says not to use a flex pvc or sweep fittings (what are sweep fittings?)<<Gradual turns... like a wave, instead of an elbow. RMF>> why is this? <To be perfectly honest, I'd consult the manufacturer on this one. I would not deviate from the suggested plumbing arrangements!> The dolphin site gave specs on figuring head pressure according how many feet to add if using 90, 45 degree angles etc.. but it never said anything about "T's. And last (sorry long winded). I have been researching different ways to return water to main tank w/o the use of powerheads. Possibly going with manifold return. IYE what are some different ways you have seen that are affective at good returns? Thanks Bryan. <Well, Bryan, I've seen some neat manifold returns that worked great! They were placed above the tank, and plumbed to a line that ran in a loop around the tank's inside perimeter, with lots of outlets along the way. Amazing water movement if done right! Also, I've seen closed lop systems plumbed to Sea Swirl return devices that are wonderfully effective, too. Lots of neat ways to accomplish this. Check out the do-it-yourself site OzReef for lots of neat ideas, or pick up Anthony Calfo's "Book of Coral Propagation" for other possible setups. Good luck, and have fun! Regards, Scott F>

Making Waves! (Circulation Enhancement) Hi guys, <Hi there! Scott F. with you!> I am renovating my 110g marine aquarium, and the first issue I am covering is the water circulation. At the moment it is pitiful with only a couple of powerheads. I am considering a centralized system powered by a single pump supplying approximately 6 - 8 outlet points placed systematically around the aquarium. <That sounds like a nice idea!> I am having difficulty designing a suitable system, at the moment making a PVC system with individualized gate valves on each outlet pipe seems like an unwieldy project that would not look subtle enough. <My thinking exactly> I wonder if you could advise me on the suitability of using 3 spray bars, each the length of my tank, along with 2 powerheads to cover lateral laminar flow. I understand that spray bars are prone to clogging up with coralline algae, and that is my principal reservation on this option. <That is actually my main concern with spray bars, too.> Do you think this project would be of use in a saltwater tank - http://www.tomgriffin.com/aquasource/DIYjuly01a.shtml <It's a nice project, and a useful end product, as long as it is maintained and algae doesn't become a factor. I am partial to a closed loop concept with say, two or three Sea Swirl rotating return devices. Yes, there is an added electrical consideration (minimal with the Sea Swirls), but these will create a very nice current pattern if configured properly. Check them out!> Thank you, and apologies for the longwinded email Regards Andrew Hough <Any time, Andrew! Good luck with your project! Regards, Scott F>

Circulation Plans and PVC Sizing Hi Crew, I'm trying to create a plan for circulation for a reef project that will kick-off this Spring. <Ooooh, sounds like fun!> I want to find out the "best practices" as per the WWM Crew. My planned tank is a 400g (96"x24"x40") on a 30" stand with Ecosystem 7222 Filtration sump (72"x22"x20) adding roughly another 100g (net). I want to run 2-3 external pumps for redundancy and do not want any powerheads in the tank. After reading the Circulation FAQs and Anthony's BOCP section on the same topic, I believe I understand how water can re-enter the tank. I'm still having a hard time visualizing exact details of water leaving the tank beyond the generalities. I'm going to thank you in advance for answering these questions (they will be numerous). I consider WWM my final authority on theplans for my tank. My questions follow: - The FAQs, Bob's CMA, and Anthony's BOCP talk about 10x circulation per hour being mediocre and new standards being 20x or more. What should I be targeting here with SPS in mind? <20X> Also, should I be calculating based to max total gallonage (500g), total gallonage less displacement from rocks (at 1lb Fiji LR per gallon, how would I calculate this number), or max tank volume only (400g). <This is the circulation of the display itself, so the total volume of the display, 400 gallons.> - I was reading up on the friction loss and head with PVC pipe. Do you agree with these calculations as the best way to determine actual flow --> http://www.moneysaverpumps.com/TDH.htm or should I trust Dolphin's version here --> http://www.dolphinpumps.com/plumbing.htm . Also, is it really important to keep the flow rate velocity to under 5 feet per second as the first site indicates? (Which of course leads to larger pipe sizing and my next question.) - Given your recommended flow rate for my application, what size PVC would correspond to that recommendation? - Do you have a link or could tell me what max flow rate to expect through various pipe sizes? I am specifically interested in the max-flow rates for 1.5" and 2" pipes to correspond to the Dolphin AmpMaster 3000 and 4000 pumps (they draw 1 and 1.3 amps respectively). - I know that increasing pipe diameter reduces friction, but how do I calculate the flow of a specific outlet after introducing Tees in the manifold plan suggested in BOCP (I'm thinking that I would divide the flow-rate evenly for equal sized Tee's? But what was the flow through that segment of pipe?) <There are a number of sites that have calculators to figure pipe sizes, flow rates, head pressure, etc. Reef Central has a decent version. I would go with the pump manufacturers recommendations regarding pipe sizes to achieve the performance you want. Make sure you sufficiently oversize your pump and pipe sizes and pipe sizes on your overflows, they are very hard to increase once installed. Better to go bigger and use appropriate valves. PLEASE make sure you drill siphon breaks in your returns to stop siphoning in power outages, etc.> - Given the 40" tank height, how far down should holes be drilled for closed loop circulation or should near surface overflow holes be drilled? Also, I'm having a hard time visualizing Anthony's surface overflow shelf (and that's after seeing the picture -- help!) <Depends on inhabitants. Want anemones? I would use surface overflows or incredibly well shielded intakes. If you size your overflows adequately or have enough of them, you can feed the closed circulation system off of the sump and return to the sump via existing overflows (no additional overflows). The surface overflow shelf is just a full length skimmer/overflow box. It is a raised lip that skims from the full length and has bulkheads below the lip for drainage. Imagine a skimmer/overflow box that runs across the full length of the back of the tank.> - The FAQs state that I should be able to find closed-loop circulation plans on the web, but mostly, people just state that have one. Could you detail this here or point to a link? <This is exactly the same principle as the return system, except the 20X circulation applies to the closed loop system.> - Finally, when calculating head pressure for the vertical lift of water on a closed loop, do I use the total head height of 70" (30" stand + 40" tank) or the total height less the point where the tank is drilled for the intake (if drilled 10" from the tank bottom, would that would be 50" [30" stand + 40" tank - 30" point of drilling for closed loop]) Thanks again, Rob <Okay Rob, head height is measured from water surface to water surface no matter what system you are plumbing. So, it's from the top of the sump water level to the top of the display water level. Same for the skimmer/return/sump system, refugiums, etc. Again, just make sure you oversize enough to compensate for head height, plumbing, fittings, valves, etc. This is especially true on the overflows. Do a web search on Durso overflows and venting. More than anything, have fun! Craig>

Circulation Plans and PVC Sizing Hi Crew, <cheers> I'm trying to create a plan for circulation for a reef project that will kick-off this Spring. I want to find out the "best practices" as per the WWM Crew. <best flow will be determined by species/genera kept instead... Stylophora and Porites require staggeringly strong water flows while Montipora can only tolerate moderate at best. Like lighting, your coral species selection will dictate hardware needed> My planned tank is a 400g (96"x24"x40") on a 30" stand with Ecosystem 7222 Filtration sump (72"x22"x20) adding roughly another 100g (net). I want to run 2-3 external pumps for redundancy and do not want any powerheads in the tank. <very good to avoid powerheads> After reading the Circulation FAQs and Anthony's BOCP section on the same topic, I believe I understand how water can re-enter the tank. I'm still having a hard time visualizing exact details of water leaving the tank beyond the generalities. <this is very much a case of needing to see the plumbing in person. Do seek a regional aquarist on one the message boards and in a local aquarium club to see their systems for perspective. Reefcentral has a forum of national aquarium societies and here on wetwebmedia.com we have a list of many in our links. I assure you that is will be well worth the road trip. Show up with beer and it will be smooth sailing <G>> I'm going to thank you in advance for answering these questions (they will be numerous). I consider WWM my final authority on the plans for my tank. My questions follow:- The FAQs, Bob's CMA, and Anthony's BOCP talk about 10x circulation per hour being mediocre and new standards being 20x or more. <true> What should I be targeting here with SPS in mind? <as per species... since you have the BOCP1... see notes in each family and genera section on flow requirements and do try to amass a most compatible collection> Also, should I be calculating based to max total gallonage (500g), total gallonage less displacement from rocks (at 1lb Fiji LR per gallon, how would I calculate this number), or max tank volume only (400g). <there is no golden rule... 20X is not literal... your very rockscape will influence the flow dramatically... very experimental here. Just get into the ballpark with flow (20x) and make fine tuned adjustments with output nozzles> I was reading up on the friction loss and head with PVC pipe. Do you agree with these calculations as the best way to determine actual flow --> http://www.moneysaverpumps.com/TDH.htm or should I trust Dolphin's version here --> http://www.dolphinpumps.com/plumbing.htm . Also, is it really important to keep the flow rate velocity to under 5 feet per second as the first site indicates? (Which of course leads to larger pipe sizing and my next question.) <wow... way too much math here for me to enjoy a very organic experience... Please do spend more time thinking about the corals in their 3-d environment rather than looking for a magic number, my friend> Given your recommended flow rate for my application, what size PVC would correspond to that recommendation? <that is dictated by the pumps needs/rating which has been sized by the corals needs <G>. Still... I suspect you will end up with 1" lines.> Do you have a link or could tell me what max flow rate to >expect through various pipe sizes? <Hmmm... it sounds to me like you have a genuine appreciation for the hard science of it all. Let me suggest you buy Escobar's "Aquatic Systems Engineering". Amazing and tell all on these various specs you seek> I am specifically interested in the max-flow rates for 1.5" and 2" pipes to correspond to the Dolphin AmpMaster 3000 and 4000 pumps (they draw 1 and 1.3 amps respectively). <wow... expensive to run... QC issues... and perhaps oversized for your needs here. Have you looked at two big Iwakis?> I know that increasing pipe diameter reduces friction, buthow do I calculate the flow of a specific outlet after introducing Tees in the manifold plan suggested in BOCP (I'm thinking that I would divide the flow-rate evenly for equal sized Tee's? But what was the flow through that segment of pipe?) <likely a moot point with a properly and slightly oversized pump, a flow meter (cheap enough and fun for you) and a bleeder line> Given the 40" tank height, how far down should holes be drilled for closed loop circulation <not important with properly guarded intakes (in and out... out guarded for fear of power failure and fish swimming in)> or should near surface overflow holes be drilled? Also, I'm having a hard time visualizing Anthony's surface overflow shelf (and that's after seeing the picture -- help!) > The FAQs state that I should be able to find closed-loop circulation plans on the web, but mostly, people just state that have one. Could you detail this here or point to a link? Finally, when calculating head pressure for the vertical lift of water on a closed loop, do I use the total head height of 70" (30" stand + 40" tank) or the total height less the point where the tank is drilled for the intake (if drilled 10" from the tank bottom, would that would be 40" [30" stand + 40" tank - 30" point of drilling for closed loop]) Thanks again, Rob <I do believe you will be very satisfied to read Aquatic Systems Engineering and a visit to a local aquarists tank will be priceless. Just visit some big message boards and post a thread stating your general location and that you are searching for a local aquarist to chat with or are looking for a local aquarium society. Sites like ReefCentral are huge with many thousands of browsers. Best regards, Anthony>

Bubbles Quick Question: The return from my upstream refugium has very turbulent flow as it drops into my 80G FOWLR tank. This produces thousands of microbubbles. I've heard that these can hurt my fish. Any cause for concern? <Possibly some cause... please read through the FAQs files for solutions starting here: http://www.wetwebmedia.com/pbfaqsmar.htm and continuing onward. Bob Fenner> Thanks again for your ongoing help. Steve

- Circulation Questions - Howdy guys, <Howdy... JasonC here.> Bryan again and have a few questions. I am on the last steps of plumbing my 75 gallon tank and have a few questions on the return flow. I have 2 1.5" bulkheads on the back of the tank, flowing to a sump under the stand. A MAG 18 in-line from the sump to return to main display. (Will be going with mainly soft corals). The return flow is by way of a manifold like Anthony describes in his book...here lies the question. I am using the black flexible ball and socket tubing running off of various "T's around the manifold. Been going through F&Q's and still need some input. How many teed outlets or "nozzles" should be applied and in what direction should the outlets face in the water column to produce a random turbulent flow? <That is completely up to you. There are no set rules here.> Right now I have a rough draft of 4 nozzles...2 in the back facing middle front, 2 on each side facing each other. What do you think? <Sounds fine.> Couple more quick questions. Make up water for either evaporation or even to be used for water exchange/change. I have a 30 some gallon Rubbermaid trash can w/ wheels and a lid. What are the time limits or amount of time someone can keep make up water in the container (keeping the lid on and aerated, possibly heated) <Several weeks, but only if it's aerated and better if there is also a pump in there keeping things moving.> I was thinking about having a separate container for evaporation water and filling it w/ my RO once a month and using this. Good/bad idea. <Good idea.> Last thing and more just curiosity from doing some reading and looking at chat/community sites. Why are Marc Weiss products bad (just gimmicks to make money.. ex. Black Powder) just wondering. <Well... no ingredients are listed which is enough on its own to make me skeptical. Also, the claims made are extraordinary. Likewise, the majority of his products contain simple sugars which isn't really 'magic' at all. Just really an attempt to separate you from your money without genuine results.> Oh yea, almost forgot, IYO what due you think or have heard about ESV brand of product/supplements (other than 2-part B ionic). Thanks again Bryan. <Cheers, J -- >

Circulation Hi! I have a real quick question - In our 38 (or 37) gallon tank, we have a Marineland Emperor 280 powerfilter (using the cartridges and bio-wheel, no media added yet) and a Penguin power sponge filter (170 GPH). The sponge filter has a venturi valve on it, and when it's open it puts out plenty of air bubbles as well as a current. Is this what I want? Or do I want the venturi valve shut off and just have a current going? Oh, and there's 18 lbs. Fiji live rock and 40 lbs. of live sand in the tank. Thanks, Alex Mills <I would not use the venturi. Please investigate the various marine circulation set-ups, protein skimming and "natural" benefits of LR and LS in the marine section of WetWebMedia.com. Depending on inhabitants you will need in excess of 10-20 times turnover (400-800 gallons per hour) direct circulation (not through a filter). There is much info in the marine section. Craig>

Sand and Tank Setup Question Thanks for the response. In regards to the separate pump that would be used for circulation, would I be able to have it pull water from the overflow box next to the pipe that fills the sump (drill a second hole in the bottom)? <This would likely suck in a great deal of air and create microbubbles.> What would be the recommended gph and size of PVC or hoses? <10-20 times the volume of your tank turned over per hour for total circulation. The size pipe is dictated by the pump recommendations. Most will give you X gph through 1" PVC vs. Y gph vs. 1 1/2" PVC.> For the return from the circulation pump, would it be better to have a piece of PVC pipe with small holes in it, run along the length of the back of the tank just above the DSB, <This spray bar idea has been used before. I don't particularly care for them. I have seen them become plugged up to much. Also, you need to consider in the event of a power outage, all your pipe work will then act like a siphon. Ones at the bottom will drain your tank into (and likely out of and onto the floor) your sump. There are ways to deal with this. Please search through the plumbing FAQ's for additional information.> or drill two holes in the back bottom corners of the tank and have the water shoot up towards the center of the tank (assuming there is no live rock in the way). <The same back siphoning problem would exist.> For the main flow to the sump, what would be the recommended pipe size, as well as from the pump back to the tank? <See above> Could I put the substrate that I remove from my existing 75 gallon tank into my sump with some live rock, or would there be too much current through there, assuming that I am using the Iwaki WMD30RLXT or MD30RLXT pump. <My problem was with the old material and how coarse it is, not where you place it.> Now for a subject change, I purchased a Colt Coral about 3 or 4 weeks ago. It came from a tank in the LFS that only had 1 actinic and 1 white bulb, so needless to say it was not very bright. It was placed about midway up the tank, and was opened up pretty nicely (maybe it was trying to get more light in a low light situation). <Yes, panning.> When I got it home, I put it on the bottom of my tank, partially under a ledge. I have 1 10,000K 110 watt VHO, 1 03 VHO, 1 96 watt 10,000K PC and one 03 PC, so it has considerably more light that at the LFS. It does not want to open up, at least not fully. It tries but doesn't quite seem to do it. The salinity is 1.025, pH is 8.4 (dip strip test kits, hard to read, but regardless, it has been consistent), dKH has been around 10-12, and the calcium is low, around 280. I am having a bit of trouble getting it to go higher. I have C-Balance, but I have not been putting it in since it is not balanced yet. After the water changes, the alk is around 10 or 11, the tap water by itself has a dKH of 7. I have been adding some RO water to see if it brings down the dKH a little, don't know if that is the right thing to do. I have been adding part A of the C-Balance only, trying to get the calcium up, but it doesn't move to much. <This is not good, similar to the problems with using CaCl products. Get your water change water in the appropriate ranges and your tank will eventually work out. Once, calcium and alkalinity are proportional, you can resume using your two=part additives.> Could it be a magnesium problem? <Perhaps, but I would double check your new salt water, too.> I use Instant Ocean salt, but no other additives. I have been changing the water every 2 to 3 weeks, about 15% to 25%. Do you think it just needs to get used to the tank, or is there too much light? <It cold be getting consumed that quickly, but your lighting is only partially related. I would not change that.> I would like to get up one morning and see it open and happy! <In time you will.> Hope you guys have a great Christmas, best wishes to all of you! Thank you, Paul T <You are welcome. -Steven Pro>

The plan using motorized ball valves Great. I'm glad I'm on a good track. Would you then encourage the following plan for a 200 gallon tank with a remote sump in the basement: 1) Iwaki RLT 100 returning water from the sump to the tank splitting into two returns with the water alternating between them on a motorized ball valve. <Sure> 2) A closed loop also splitting into two returns with the water alternating between them on a motorized ball valve. The height of the returns inside the tank for the closed loop would be lower than the sump returns in order to create water circulation at a different level of the tank. The returns would be hidden in the rockwork. Any suggestions how high these returns should be if the tank is 24" high? <Mid level and also use two intakes as well as two returns to diffuse the pressure of the suction.> 3) I'm told that head pressure for a closed loop is not much an issue and so an Iwaki RLT 70 or 55 might be too much. So maybe the Iwaki RXLT, which is not rated for pressure, is the right choice, say the RXLT 30 or 40? <Do look at the flow charts provided by Iwaki and reprinted by just about any e-tailer to find the one that fits your needs.> 4) I like this plan, but for the fact that it contemplates only one pump returning water from the sump. I could have an unused pump in reserve in case of failure, but you previously raised the following concerns to this contingency plan, which have merit: "I am an aquarium maintenance professional that works out of his home, so I see things from that perspective. While for you and your own tank, you maybe perfectly happy with a spare pump sitting unused in the house. I don't want any more stuff than I already have to have around and I doubt any of my customers would want one either. I try to consider every possible catastrophe and design systems so that no matter what goes wrong they will continue to function and not flood. It is a liability issue for me. Also, if a pump were to fail, with two pumps, I can get to replacing the broken one when I have time. If there is only one main pump, I would have to drop every to fix it immediately." I'm concerned about having too may sump return pipes in my tank, but maybe should just overcome that concern for the sake of safety, right? P.S. I'm puzzled by how the second pump would keep the sump from backfilling. Wouldn't the sump returns on the loop with the failed pump siphon back water to the sump in such large quantities that the second pump would not be able to keep up and pump back sufficient amounts to keep the sump from being overwhelmed? <You have a good question. Allow me to clarify. I always plumb the two return pumps on separate lines. In the event ones breaks (which is a very rare occurrence), the back siphoning one will over power the one pumping against head pressure. But that works to your advantage because the back siphoning one will soon suck up enough air to break the siphon and then just sit there. You get some of these benefits with a closed loop. If either one breaks, you will still have some circulation. But, if the return pump fails you loss your heaters, chillers, protein skimmers, carbon filtration, and everything else you hide in the sump. With two return pumps, all of these can still function. Best of luck to you! -Steven Pro>

Wavemaker on the valves, not the pump Using motorized ball valves seems like a good way to go in order to create chaotic flow for a reef tank. As described in the link below, instead of the wavemaker turning the pumps on and off, this fellow engineered his system so the three way valve opens and closes, directing the water to the left and then to the right. Presumably, this is much better for the pumps, I think. http://www.rockcanyon.com/reef/flow.htm Is there any downside to this approach? <The only downside is expense and maintenance/possibility of failure, but this seems like a very nice idea and different than powerhead/wavemaker combinations the pumps are running at 100% all the time. -Steven Pro>

Bubbling Away Scum! By way of a follow up to the question posed in the posting" Cleaning "Scum" on water surface!" I notice in my 29 gallon reef tank that if I run an air stone and create surface bubbles, I have no observable protein buildup on the surface of the water. I run an H.O.T. (I'm having a senior moment and can't remember the type but it is one of the ones you all always recommend.) The skimmer works flawlessly but I don't have an overflow attachment with it. <Certainly not absolutely necessary to have a surface overflow, but the majority of proteins and organics accumulate at or near the surface, so protein skimming is enhanced by drawing water from this area> Do you see a problem with running the air stone other than the salt creep and increased rate of evaporation? <Not really. I think that they help rid the water of CO2 and do break up the surface tension, enhancing gas exchange. Just make sure that you change them often, so that clogged airstones don't put excessive back pressure on your air pump.> William Snyder Stuart, FL <And thanks for stopping by, William. Regards, Scott F>

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

Bula from Fiji Bob! <Bula my friend> Tim McLeod of Walt Smith Int. suggested I email you with a question.... <Hello to Tim and Flower> We have an 800 gal display tank with a 1000 gal reservoir tank, so we circulate 1,800 gallons of salt water through the display. We are building a 400 gal tank in to the system in which we will grow mangrove and bonsai them (see http://www.fukubonsai.com/5a9.html It can be done!!!). <Yes> In this mangrove tank we plan to create an ecosystem and feed the nutrients & organisms in to the display tank to feed the corals. <Okay> This will require us pumping from the mangrove tank to the display tank. We are concerned that using impeller pumps will "mash" the live organisms we created and make the whole exercise pointless, however, we are having trouble finding diaphragm pumps that are a) electric b) salt proof c) continuous duty and d) rated at 400 to 600 gallons per hour. Do you think an impeller pump is out and where could we find the right diaphragm pump if impellers can't be used? <Actually not much of a problem. Some studies have been done which show less than 1% of crustaceans, worms die as a consequence of passing through paddle-wheel like impellers. Those critters are tough!> Appreciate any advice Bob and please come see us when you visit Fiji!! <Will do so Phil. Bob Fenner> Vinaka Phil Felstead Kula Eco Park P.O. Box 823 Sigatoka Fiji Islands Tel: (679) 650 0505 Fax: (679) 652 0202 Email: mitman@connect.com.fj Web Site: www.fijiwild.com

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

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

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

Undersized overflows All Glass tank overflows I have tested can have a flow rate of 700 gal per hour for each one. The way to do this is to used 1-1/4 pipe or tubing on the leaving side of the bulkhead to the sump. Used a Durso set up on the top side. All overflows on the 75 gal 90 gal will have 700 gal per hour. <10X turnover is adequate for fish only tanks...perhaps. But with the modern popularity of packed reef displays and stony corals... this is about half of what is needed. Hardly "reef ready" as the claims go. And impossible to upgrade if the consumer buys it and wants to put an averaged sized water pump on (most mid range pumps fall 1000-1500 GPH). So one cannot run enough flow through these overflows to keep sps corals, for example. A consumer must then contend with a custom drilling for extra holes (closed loop or other) or just have too many power heads in the main display to get enough water movement for coral health and growth (and to prevent detritus from building up). Adding heat from PHs and considerable expense overall to the project. Seems like it would just be more sensible for the mfg to provide larger holes. Plenty of room in the overflow tower. No harm if its bigger than some buyers need... it will just run at a safer level. Makes no sense to me if the R&D people actually own reef tanks and test these systems before they go marketing them as reef ready> The 120 180 gal tanks will have two overflows that will give 1400 gal per hour. <1400 GPH (and running dangerously at max for this overflow) is still a trickle in a 180 gallon reef). I have no qualm with the quality of construction... just the inappropriate marketing as "reef ready"> The elec. power has come back on too many days with out it. Thank you for the help solar works well. Gibson <that means the clam survived? I hope so my friend. Best regards>

Plumbing issues These plumbing questions are in reference to a 180 gallon reef tank with the sump in the basement. In order to create water movement in the tank, I understand that there are three options: (1) external pumps only generating strong return flow, (2) internal pumps (such as powerheads), or (3) a combination of the foregoing. The first option seems the best, at least from the perspective of not having equipment in the tank, but it's more expensive and generates heat. <Actually, you are incorrect on the second two parts, about expense and heat. External pumps pass on much less heat into the water than powerheads and are comparable in price for the gph they generate. The expense part comes into play for you in particular because you are locating your sump in the basement. For most people, with sumps in their stands, external pumps are comparable.> Is it worth it? <Yes> If I go with the first option, at least one opinion counsels having two pumps running in tandem (in case of power failure?). I guess the return outlets go back through the internal overflow (4 or 6 holes?). A wavemaker could be coupled with this, thus alternating the flow among these returns. <External pumps are built for continuous use. Using a wavemaker on them could shorten their lifespan.> Does this make sense? Under this setup would there be any need to have some other internal pump arrangement (e.g. powerheads in addition or SeaSwirls?). <You should be able to create enough random, turbulent flow with external pumps that a wavemaker, powerheads, or other devices would be unnecessary.> >As a separate issue, there's the noise from the overflow, to which I believe you have referred other inquiries to the Durso standpipe and other such devices. However, I was advised that this could somehow increase the risk of flooding, to which my contractor responded as follows: <Unlikely> "The absolute best system with 100% no chance of overflow is the way I configured my overflow [which is to drill the holes in the back of the tank at the water line]. It again has 4 1" through fittings with strainers connected indirect to a 2" line back to the sump. If you think a 1-1/2" line can get clogged go to a 2" or even a three inch return line. If it were me I would have 8 - 1" through fittings manifolded down to a 3" return line." Is he right? As always, your guide through this thicket of opinions is most helpful. Thanks. <You are welcome.> Sea swirls are the very best for wave making. I would recommend 2 - 1" sea swirls in a 6' long tank and have 2 Iwaki pressure pumps powering them. I would also run 2 - 1" return lines from the pumps <You may need 1 1/2" or even 2" return lines from your basement. -Steven Pro>

Circulation Hello! <Hi there! Scott F. here today!> I've got a question about circulation in my 90g cube tank using external powerheads. I don't want to see any powerheads in my display. I'm going to keep anemones and Clownfishes and I should have strong current. <Agreed> My tank will have 40kg of liverock, 25 l of bioballs and sump in overflow like in the picture attached. My circulation will be done using two external pumps 3500 l/h each. Ten hours a day (With HQI) both of them will be on. Each pump has two outlets in two corners of display and the flow will cross in the middle of the tank. At night flow is reduced and right/left pump in on periodically for 15 min each. What do you think of this system. <Sounds really nice...A suggestion: You may want to just leave the flow on constantly, as opposed to cycled. It's easier on your pumps, for one thing, and-as long as you have set up a chaotic flow pattern (which it seems like you have done), you should be fine.> this will probably make a water level changes in my display (what do you think - my overflow is 70 cm) Best regards Darek <Hard to say, but it is a possibility. I'd think more about water level fluctuating as a result of evaporation, instead. I think that you'll be fine. Good luck!>

20 Gallon Circulation Question Hello Crew (Bob, Anthony, Jason, Steven)! <Our crew has grown considerably now to include Scott, Craig, Gage, and David.> Thanks to all of you once again for providing such an informative and valuable service to all of us Marine newbies. I have been in the hobby as a freshwater aquarist for nearly 25 years and have decided to take the plunge into marine life. I have read through many of the WWM FAQs regarding circulation and alas I still have some questions. I am setting up a 20 gallon tank which I would like to use for invertebrates, fish, and live rock mostly, with the possible addition of some mushrooms, leathers, or open brains down the road. I currently have only a dual lamp light hood with two 15 watt NO fluorescent bulbs, one trichromatic, and one actinic. I have ordered a 96 watt PC fixture which should be here soon. <To replace the other?> For filtration, I have a hang-on Marineland Emperor 280 g.p.h. bio-wheel filter. I do not have a skimmer yet, but plan on buying the Aqua-C Remora which will add another 85 g.p.h. of water turn-over in my tank. <A fine skimmer, that will allow you to easily upgrade to a larger tank in the future. On the other hand, we generally do not consider skimmers as part of the circulation.> These two items combined should take me up to an approximately turn-over rate of 18 times per hour. Most posts I find in the FAQ list a turn-over rate of 10 times per hour as the minimum, however I have seen posts that suggest turn-over rates of up to 40 times per hour. <Yes, depending on what the person wants to keep. For your situation, 10 times is fine.> Given the 35 lbs. of live rock that I am currently curing in the otherwise bare tank, will this be enough current/circulation for me long-term with this set-up? Will I/should I need to add one or two powerheads for additional circulation? <Yes, one to change up the laminar flow that will come from the Emperor and the Remora to an extent. Both will provide a constant flow of water across the top of the tank, from back to front. One or two small powerheads should be added to provide some more turbulent/random flow.> If the powerheads are not necessary now, will they be necessary when I reach the point where I plan to add the mushrooms or leather corals? <You will need them more for the Leathers than for anything else.> Any other suggestions are greatly encouraged and appreciated. I'm very sorry to add yet another question to what I am sure is already a staggering count. Your dedicated efforts to the advancement of our hobby are most appreciated (especially for us newbies). Kindest Regards, Jim Troeger <You are quite welcome. -Steven Pro>

20 Gallon Circulation Question II Steven, Thank you for your quick response. To answer your question below regarding my 96 watt PC fixture, yes, the intent was to have it replace the other two-bulb All-Glass light strip. Since that point in time, however, I have actually begun to seriously consider the Helios 24" 110W PCT setup. It has two 55 watt bulbs, one actinic, one 10,000K. Will this be too much light for my 20, or should it be about right? <It is pretty bright but you should be able to adapt your intended purchases to it. One the other hand, I hate to waste stuff. You have the NO fixture. If you change both lamps to actinics and add a single 32 watt full spectrum PC, you should be just fine and save money, too.> Also, if I go the route you had suggested with adding a 32 PC full spectrum lamp in addition to two actinic bulbs in the two-light strip, what type of bulb placement should I use? Actinics to the rear? The front? Doesn't matter? <I usually place the actinics in the front, but I don't think it matters too much. I think it may help keep algae on the front glass to a minimum, but I have not really experimented with this, just a gut feeling.> Any additional suggestions you may have on flow ratings of powerheads to use and placement suggestions would be most generously appreciated. <One or two 100 gph pumps should be ok. You are going to have to play around with them so they create some turbulent conditions in your tank with the rock work.> Your comment on changing the laminar flow would seem to indicate to me that the powerhead should be placed on the end of the tank discharging straight across to the other end. Is this correct? <It is going to depend. You should be able to see the currents once you get some stuff in there.> Should I mount it high, middle, or low? If low, in front of, behind, or straight at the live rock? <Play around with them and see what works best. Try two at opposite ends aimed at one another or ...> Should I remove the BioWheel now, or wait until the live rock cycles and my protein skimmer arrive? Also, what is your concern with the BioWheel... too much creation of nitrites for the tank? <Bingo> Also, would something such as a Aqua Clear Wet/Dry be better here, or not necessarily? <Not necessary with the liverock.> Thank you once again for this amazing service! Jim Troeger <You are welcome. -Steven Pro>

Overflowing With Questions I am building a reef tank and have a question about overflow box location and drain hole size. My proposed reef tank will be 84Lx24wx26(or 28)H. The sump/refugium will be located in the basement and the reef tank on the main floor. <A great set up!> I want to have just one overflow located at the back center of the tank; rather than one at each end. The single middle overflow would increase the viewing areas at the sides. <There are ways to do this...> First: Is there any problems with having just one middle overflow with that size tank? It concerns me because all the manufactures build corner overflows at each end/corner. <Although it certainly can be done with one overflow, I think that two would be a little better. Another idea, which Anthony Calfo touches on in his "Book of Coral Propagation (BTW- Just get this book- it's awesome, and you'll love it!) is to construct an overflow that runs the length of the aquarium, built near the top of the tank, with holes drilled directly into the walls of the tank. In essence, what you will have is a small shelf, which can be a neat place to place frags, etc. This is definitely a radical idea, but will efficiently pull water from the top of the water column in an efficient manner.> Second: How large should the drain hole be in the bottom of the tank? <Depends on the size of the pump and its flow. Larger (1-1/2" or more) is generally better, IMO> Should I drill one large hole or two side by side? How big? I will be using a Durso stand pipe to eliminate noise. I want to eliminate the chance that the drain does not plug and overflow the tank. Plus I am concerned one large hole may not be enough when using a stand pipe. <Agreed- one overflow is probably not enough. I'd definitely use two, maybe more, depending on the pump size/water flow that you are shooting for. Durso standpipes work well, too!> Third: Do you find 28" high reef tanks too tall? I plan to use MH and VHO combo lights. Thanks for your help. Greg <I don't think that the tank is too tall. I tend to favor wider, shallow tanks for ease of maintenance, light penetration, and aquascaping possibilities, but tall tanks work well, too, particularly if you are using a deep sand bed, creating extensive, tall aquascaping features, etc. Your lighting scheme should work; again- the suitability is largely based upon the types of animals that you will be keeping, and the wattage of the bulbs. Many, many possibilities. Have fun! Scott F.>

Re: Overflowing With Questions... Thanks for the quick response and the thoughtful reply. What a fantastic resource you are! <We sure have a great group of people working here! Thanks for the encouraging words!> Another question, though. I am thinking about going to a 120 Oceanic "reef ready" set up, with two built-in overflows. I think I remember reading in one of your postings that you (in the collective) did not particularly like overflows. Is there another option for water circulation? <To the contrary, IMO- well- designed and constructed internal overflows are the standard, preferred method of getting water into the sump from the aquarium. I feel that they are a great way to go! Maybe you were confusing external overflows, which can be problematic and can break siphon> I have a Medusa heater/chiller controller and a 1/4 HP chiller, so I need to pump water through the chiller on the way back to the tank from the sump. <An efficient overflow setup with a capable pump should do the trick!> Thanks again! <And thank you for visiting the wetwebmedia.com site. Do check on the many resources that we have regarding set-ups and sump configurations. Regards, Scott F>

Bubbles in Sump Hi Crew, I have read a number of FAQ's on microbubbles in sump but not able to solve the problem. I have a 200 gallon tank with the sump (72 gallons) in basement. There is about a 8 foot drop for my 2 inch PVC pipes (2 of them) to run from the overflow to the sump so when the water reaches the sump it crashes and generates significant bubbles (almost looks like a foam). I have ordered an Aqua-C EV240 but not set up yet so I know the problem is not the skimmer nor any pinhole leaks in my return plumbing (that has all been checked). I have put a sponge and tried to put up a couple of baffles but my Iwaki 100 RLT pulls the water through the sump quickly and the bubbles continue to get pulled through. What type of materials will actually trap these bubbles or is there a way to modify my sump so as to capture them in an area and have them pop before getting back into the return. <The easiest fix is going to be to add two micron filter bags to the drain lines. These should stop the microbubbles, but they will require cleaning almost every single day. If that gets too tiresome, I would modify your sump with baffles, forcing the water to go under and then over two planes. This should force most of the bubbles to the surface to burst before the return pump.> Thanks in advance, Joe <Best of luck to you. -Steven Pro>

Puffer Trauma... another intake injury I ve been referred to you by to very smart people. Last night I arrive home late, to hear a loud noise coming from my 45 gallon tank. When I tried on the light, my puffer was caught in my uv sterilizer pump. normally he's around 4inches long, but when I first saw him he was the size of a baseball. The pump caught about 2 cm behind his side fin, at first he was dazed and messed up, then my lion came out and start picking on him, well I solved that and the lion is no longer in the tank. Its been around 20 hours, he still swimming slow but is now back to normal color, only this one side is all white, looks like necrotic tissue. <May well be> He wont eat and is apparently hurt, this fish means the world to me! I have a 45 gallon, with some live rock and only 1 small star polyp, other fish include small Picasso trigger, new yellow tang, and two damsels. I have a 15 watt uv sterilizer, back pack protein skimmer and AquaClear filter, lighting I have 440 watt ice cap with VHO's. Please help Thank you very much <The only real course of action is to keep the system stable and optimized, and hope... plus of course put a screen cover over that pump intake. In all likelihood, if this puffer is alive at this point, it will heal... though it may not eat for several days more. Bob Fenner> David White University of Michigan School of Dentistry Ann Arbor MI

Re: water circulation Hi guys. I am planning a standard size 90 gal reef setup. I used your site to answer just about all my questions without even writing to you. Anyway, I just wanted to run through a simple water flow and ask for your input/approval. I plan on having four 1" bulkheads on the 90 draining into a 55 gal sump underneath. If I understand things correctly than this should be somewhere around 1200gph draining right. <Do think about doubling the size of your overflows and bulkheads, and look into Durso pipe type vents to avoid noise. The noise is really sucking air. Give it a bigger drain and a place to vent air.> The return would be supplied by 1" ID, reduced to a 3/4" manifold system, all powered by an Iwaki MD70RLT (which I'm sure you know is rated at 1500gph). Do you think this will give me adequate water flow for a 90 gal without running into problems such as gurgling jungle noises from the overflows? Also, how many outlets do you think I should branch off of the manifold? I am trying to avoid the use of ugly powerheads if I can. <Oversize the manifold pipe (there may be specs in with the Iwaki to such) to maximize available flow and downsize from there. Don't forget valves. Three or four inlets would likely work well, don't forget that future refugium! It's easier to put that tee and valve in now.> Any expert advice would be greatly appreciated. Ben from Pittsburgh, who is not thrilled about Kordell Stewart being back in for the rest of the season. At any rate, Go Steelers!! <Ben, Thank your lucky stars your not writing from Seattle like I am....At least the Cougs and the Sonics are hot. Have fun with the new tank! Craig>

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

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

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

Impeller Replacement I currently have several RIO 600s that are supporting protein skimmer and are used for circulation. I am looking to replace all of the impellers and would like to know where I could purchase impellers with a ceramic shaft instead of metal. I have had some problems with rust on the metal shafts which I believe might be partly to blame for a green hair algae bloom. <Unlikely to contribute significantly to your hair algae problem, but maybe a good idea to replace anyway. Rust in marine tanks is always a bad idea. Take a look at our nuisance algae coverage on www.WetWebMedia.com when you go to the links page.> Thank you for your help, EJ <You are welcome. -Steven Pro>

Flow rate <Hi Craig, Craig here...> What is the recommended flow rate over a Marineland commercial BioWheel? I currently have a Little Giant powering the overflow onto the BioWheel in the sump tank and it is currently generating ~800GPH. Is this too fast? Should I slow it down? Does it really matter? This is a 180G FO tank with no LR. Sincerely, Craig <Marineland says the Tidepool Bio-wheel is designed for 300-600 gph. Better slow it down a bit. If you need the total turnover divert some of the flow to the media below. Good luck! Craig>

Flow rate Craig, Would it be detrimental to the system if I were to T the flow to the sump from the overflow, say half going into the BioWheel and the other draining directly into the sump? This would slow the flow rate of the BioWheel to ~300-400GPH, but I'm concerned with the water that isn't going to the BioWheel. Will this affect my bio load? Thanks for the help, Craig <No it would be fine. It doesn't affect your bio-load because the bio-load is based (should be based) on the capacity of the filter that was designed for 300-600 gph. That 200 gph gets treated next time. To be sure, test your water. Craig>

Re: 75g Set-Up Steve, at the risk of driving you crazy, I had just a few quick (being the choice word) follow-up questions regarding the 75 AGA pumping which you have been helping me with. I've figured out the PVC around the top and outlets, but more regarding the pump selection. Using the Durso standpipe design for the normal AGA overflow (out), I will also use another standpipe for the 'in' in the AGA overflow, BUT also going 'out' of the tank to the sump. This should increase the standard AGA overflow from 750 gph to 1500 gph, correct? Both standpipes will lead to my 20 gallon sump with a Plexiglas partition in the middle (dirty side). My Mag-Drive 5 (or Dolphin DP-560. Is this a better pump?) will pump water from the 'dirty side' of the sump into the Aqua-C EV 120 and discharge the protein skimmed water into the 'clean side' of the sump. Okay so far? I will fix a 1 1/2" bulkhead into the wall of the 'clean side' of the sump where 1 1/2" PVC pipe will lead to: A Mag 12 (you suggested) at 1200 gph. (I'm thinking that this will not be enough now.) OR A Dolphin AmpMaster 2100 (with 1 1/2" inlets and outlets - so it will fit the 1 1/2" PVC of the return pipe). <That is a pretty serious pump, about 2700 gph at zero head.> I was thinking that 20-30 times the 75 gallon tank per hour would be better for SPS/clams. At 20 times, that would be 1500 gph which would match my AGA overflow with the before mentioned changes of 2 Durso standpipes. If 2100 pump is too much I could even dial it back (which I understand can be done with the Dolphin AmpMaster pumps. <It would be better to T the return line and have a bleeder valve setup to recycle water back into the sump.> Otherwise I could place a turn valve on the exit or out of the pump - probably a good idea anyway if the pump ever fails. <At the risk of even more questions, let me suggest using two smaller pumps. I like to use two separate pumps so that in the event one pump breaks, the second one will get you by.> Thanks again (deja vu?), Andrew. <You are welcome. -Steven Pro>

Microbubbles II Regarding the sump as possible cause of air bubbles, doesn't seem to be, I even put up a little barrier wall before the return bulkhead in the sump (large pad of white filter floss that could capture any bubbles). Tried the Vaseline at all joints in the PVC piping but no difference. Any other ideas? The one thing I was wondering is it because there is so much turbulence from the returns at the surface of the water in the main tank that its creating all these bubbles there. <Surface turbulence is extremely unlikely to cause microbubbles. I would continue to look for another source.> Should I redirect the water flow towards the bottom of the tank? Thanks <Good luck! -Steven Pro>