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Flow rates for a large fish tank 6/22/11
I really appreciate the assistance and help you all provide as you have done in the past for me.
Anyway, after spending time reading articles on your site I had a few questions concerning flow rates for a large freshwater tank.
I have a custom 300gallon acrylic tank made of 3/4" body with dimensions of 96"wide x 30"deep x 24" high. I want to make a Malawian cichlid tank with Haplochromis and peacock species. I want to get about 3000 gallons/hour to achieve the 10X turnover rate as recommended. I have two overflows with each one having 1.5" and 1" lines. I have an 80 gallon wet dry filter and wanted to know if it is okay to drain 3000 gallons into the wet dry sump by enlarging the 1" bulkheads to 1.5" so I have four 1.5" drains feeding into the wet dry filter. I would then have a larger return pump feeding 3000 gallons/hour back to the tank over the back in a closed loop system along the top perimeter of the tank. Is there any benefit to double the flow rate through a wet dry filter to make the 10X flow rate if the filter can handle this extra capacity? I would have to drill and add two more 1.5" bulkheads to the top of the wet dry sump over the filter pad.
Another option would be to only drain 1500 gallons/hour through the two 1.5" bulkheads and returning this with a pump back through the existing 1" lines and having another 1500 gallons/hour going through a closed loop system over the back and along the top perimeter of the tank. I would then have two 1500gallon/hour pumps at the proper head height to make the 3000gallons/hour 10X flow rate. Of those two options, what would be the best option? Any other advice is also appreciated.
I also have a 125gallon All-Glass tank with overflows that I want to use as a Central American cichlid tank and wanted to apply the same approach for filtration and flow rate as the 300 gallon tank.
Thanks for the advice.
<Hello Steve. Malawian fish generally want a high flow rate, so anything between 8-10 times the volume of the tank will be ideal. I wouldn't go substantially above this level unless I was keeping very large fish or species particularly adapted to surf conditions. The way you do this doesn't matter hugely, but if you can spread out the current so there is movement at the bottom as well as the top, so much the better. Marine-style aquarium filters are very good when used with Malawians, so any of the options involving a sump and a filter outside the tank has much to commend it, especially if you can place some bags of crushed coral in the sump to provide extra buffering against pH drops. Because plants aren't a major feature of Malawian tanks, the fact the overflow and sump drive off CO2 doesn't matter. In short, choose whatever method of filtration works for you in terms of budget and maintenance. Likewise, what works for Malawians is broadly applicable to Central Americans, except that water chemistry needn't be so hard. Do be sure to read Mary Bailey's article on Peacock cichlids, here:
Re: Flow rates for a large fish tank 6/23/11
Thanks for the previous information
I was also curious about what your advice would be about the two return options about the wet dry setup with the bulkheads I mentioned earlier as seen in my previous post below. If you could provide recommendations that would be great.
<Hi Steve. I have no opinion either way! Would suggest you read this article re: bulkheads as written for the marine side of the hobby; the basic concepts hold true in a Malawian system where water quality and flow rate characteristics are very similar.
Do also read the articles Bob has penned on marine aquarium plumbing generally:
In broad terms, most overflow and sump systems work well, but certain designs, flow patterns work better than others. Cheers, Neale.>
what size bulkheads holes should
I drill into my tank and is a Quite One 5000 with 1330 gph overkill for
1 Black Piranha 9/12/10
Re: Powerhead Problems
Water flow in large
Re: Water flow in large
aquariums -- 10/31/09
Water flow on tank
Re: Water flow on tank
Water Movement, gen. FW, Angelfish sys. -- 01/22/09 Hello Crew, Hope all is doing well. I have a question about water movement please. I have been doing quite a bit of research of why it is necessary and all of the benefits. I have a 75 gallon freshwater tank with an emperor 400 power filter. Because of all I read about the importance of water movement (and to help clean my substrate) I have ordered (not received) 2 #2 Koralia water pumps. I have read that these do not shoot out sharp streams like some power heads, but more of a wide less powerful flow. Now I am starting to read some articles about how some fish actually will not do well in aquariums with water movement such as angelfish. Although I have no fish in my tank yet as it is cycling angelfish was going to be my first choice. Please help me know which fish I should not get because of water movement. Is it true that water movement is detrimental to angelfish? Thank you for your help. James <James, water movement is important for many reasons. The main three are these: even distribution of heat from the heater; cycling of oxygen from the surface to the bottom of the tank; and movement of ammonia and nitrite through the biological filter. Additional benefits include giving the fish exercise, moving solid wastes through mechanical filters, and keeping plant leaves free of detritus. In general terms, most community fish will do well in tanks with water turnover rates of 4-8 times the volume of the tank per hour. Add up the turnover from all the filters and pumps in your system, and if the total is less than 8 x 75 gallons = 600 gallons per hour, you should be fine. Yes, Pterophyllum (and indeed most laterally compressed cichlids) do not enjoy turbulent water flow, but strong, steady water flow will not harm them. If you ensure that there are some tall, upright bogwood roots in the tank, these will acts a baffles and create less mobile pockets of water, and your fish will congregate there if they need a rest. Cheers, Neale.>
Re: Water Movement Thank you Neale, I just found out that the Hydor Koralia Water Circulation Pumps I ordered supposedly have a flow rate of 600 gph each. That in addition to my emperor 400 (which probably only pumps 300 gph with media inside) is going to be way too much. How do other aquarium owners get by with having strong power heads going in their tank in addition to their regular filter? Thanks again. James <Hello James. Don't put too many pumps in the tank. While some fish actually adapt rather well to very strong water currents, Mbuna for example, Angelfish won't thank you for it. Try installing just the filter first, with just one circulation pump, and see how things go. There's no advantage to having too much water current if your fish will be stressed by it. Cheers, Neale.>
Re: Water Movement Hello Neale, and as always thanks for your advice. After our last e-mail I have been considering adding another emperor 400 to the other side of the tank for a more even water distribution. I know another filter would balance things out and keep the water flow more rapid (probably about a 600 gph turnover with both pumps going. In your opinion would you do this and leave out the other Koralia pumps I mentioned or leave in just the one power filter and use 1 of the Koralias? I want the most water flow along the bottom for detritus to move into the water column and I don't know which of the combinations would be best. Also, If I continued using just the one emperor filter and added 1 Koralia what do you think the placement would be? I know I am probably being too picky, but I want to make a new start the right way and I know from all I have been told by you just now important water movement is for a cleaner tank and happier fish. Thank you again and have a great weekend! James <James, all else being equal, your water turnover "budget" is best spent on filters. In a marine aquarium, water movement pushes water past the live rock, where it gets filtered, so adding powerheads and water pumps will indeed improve water quality. But in a freshwater aquarium all a powerhead does is push water about. That helps with oxygen and heat distribution, but has no impact on filtration. So for freshwater aquaria, while you certainly can add powerheads, it's not worth doing so INSTEAD of adding additional filters. That said, hang-on-the-back filters have pretty sucky performance when it comes to moving water about along the bottom of the tank because of their design, though this varies from model to model. I don't use them, and they aren't widely sold here in the UK, so I can't speak from experience. But I suspect you'd find at least one powerhead pushing water along the bottom of the tank quite useful. Cheers, Neale.>
Re: Water Movement, FW 1/24/09 Hello again Neale, A couple of e-mails ago you mentioned that I should add up all the gph from all filters and power heads and make sure they did not go over 600. But since my filter is a hang on the back couldn't I discount that as far as adding to currents too strong for fish since it does not move the tank water much? Thanks again, James <Hi James. The short answer is no, you shouldn't remove your filter's turnover from the overall turnover estimate, at least not at first. It may well be that once your tank is set up you'll find dead spots in the tank (flake food doesn't move, plant leaves don't sway, detritus sits on the sand). Then you can add additional pumps as required to supplement any issues specific to the filter types being used. But initially, you don't want to expose your fish to extremely high levels of water movement that they might not be adapted to. Cheers, Neale.>
Re: Water Movement 1/24/09 Dear Neale, please forgive me for continuing on this issue, but I have gotten a little confused. <Oh?> You mentioned the total gph turnover safe for fish movement in a 75 gallon would be up to 8 times the volume (75) which would equal 600 after I added up all my pumps output. <As I've said *it depends on the fish*. Surf-zone cichlids like Eretmodus or Hillstream loaches such as Gastromyzon would be happy with 10, 12 times the volume of the tank in turnover per hour. On the other hand, Angelfish would be better at around 6 times because they come from more gently flowing rivers, and tank-bred fish especially won't be used to torrential flows of water.> Like I have said before I prefer hang on the back filters because I have used them before and also because the way the cabinet under my aquarium is constructed I cannot use a canister filter because of the room constraints. <Fair enough. But whether you like them or not, and I appreciate they have some useful attributes, they aren't great filters for messy aquaria because the inlet and outlet are so close together.> If I use 2 of the emperor 400s that will be about a total gph turnover of about 600. So if I still have food and detritus on the bottom that does not move with both of these pumps operating you feel I should not add a power head to assist because of the extended amount of gph turnover? <I would certainly NOT add another pump (or filter) until you'd set the tank up with these two Emperor 400 units and seen how the fish react. If they're fine, and the water movement is not turbulent, you may want to add one or more strategically placed pumps elsewhere in the tank. My community tank operates at 8 times the volume of the tank in turnover per hour, and despite what you might think, the water flow isn't all that strong once the filters are filled with media and the tank decorated with rocks and plants that break up the water flow. But certainly try things out as they are first, and then make decisions about adding more pumps. Without seeing the tank or the decor, I can't predict precisely how the water is going to move about in this aquarium.> Is that correct? Thank you again. James <Cheers, Neale.>
Water Flow Too Powerful 12/18/08 Hello, I have a 30 long tank with just 3 mollies and about a dozen fry. My penguin 350 is too powerful for my fry to handle. However, it is ideal for the load of fish I plan to fill this tank with in the next 3 months. The fry will eventually be moved to a 30 hexagon to grow up in but I haven't started the set-up for this tank yet. In the meantime, is there a way to slow down the output water flow without compromising the efficiency of the filter? This is how I'd like to stock the 30 long: 2 Black Mollies (already in tank) 2 Silver Mollies 2 Cremecicle Mollies (1 already in tank) 2 High Fin Swordtails 2 Red Wag Platies 2 Rams 3 Corys Can my filter handle this bioload, without the fry? Audra <Try directing the outflow from the filter towards the glass instead of into the tank; the current will disperse, and the fish will be less "pushed about". Some of your fish enjoy strong water currents though, in particular the Swordtails and Corydoras, so they won't care. As your research should hopefully reveal, Mollies usually do best in tanks where salt is added, and while the Platies and Swords won't mind, the Corydoras and the Rams may well do. On the other hand, Rams need very warm (28-30 degree C) conditions, and that's much too hot for Swordtails, Platies and Corydoras. Keep the Rams too cold and they'll get sick and die. (Actually, most commercially bred Rams die within weeks anyway, and they're a fish I simply don't recommend unless you're able to buy locally bred or wild caught stock.) So over time you'll likely want to spread out your stock into tanks best suited to the needs of these various fish -- while they might be fine now, by imposing on the preferences of each species, you increase the odds of disease and poor health. For now, I'd SERIOUSLY consider keeping JUST livebearers in this one tank, maintained at about 25 C (77 F) and with a little salt added (say, 3-6 grammes of marine salt mix -- not tonic salt -- per litre of water). This will suit Mollies, Guppies, Platies and Swordtails. There are various salt-tolerant fish you could add, about which we can discuss another time. But since you're still stocking the tank, I'd heartily recommend choosing carefully now, rather than trying to fix problems later. By the way, all Mollies cross-breed, so if you want a single "sort" of Molly fry that you can share or sell back to pet stores, keep JUST ONE variety in the tank. Pet stores don't really want "mutt" Mollies that aren't any one variety, and after a while you'll be fed up with housing hundreds of fish you can't sell. Cheers, Neale.>
Re: Water Flow Too Powerful 12/18/08 Thank you, Neale, for your feedback. I'll take everything you said into consideration. <Audra, I'm happy to help. When planning an aquarium, it's wise to be prudent, and take into account the needs of all your fish. Doing so is the path to easy, low-maintenance, healthy fishkeeping! Just because Rams won't work with Mollies, doesn't mean you can't keep *any* dwarf cichlids. Consider Etroplus maculatus for example, or one of the Pelvicachromis species such as P. taeniatus. Get back in touch if you want some more ideas. Cheers, Neale.>
Water or air Pump, for moving new water for FW sys. 11/17/2008 Hello all, <Hello right back!> Hope things are going well. <Not bad, thanks for asking> I have a question about an air pump, please. I plan on keeping fresh water for my water changes in a large plastic trash can. I would like to know the smallest water pump that would be sufficient to keep the water circulated. <Assuming you mean an AIR pump to keep the water AERATED? Then you essentially answered your own question - How big a pump do you need to push the air down an air tube to the bottom of the trash can where it is then released into an air stone?> <If you're talking about a standard 35 gallon trash can you'll find that the smallest and least expensive pumps found in the average pet shops won't do the trick as they usually start to lose pressure after 14 inches or so. Also, the larger the pump, the less stress on the diaphragm for pushing the water that deep. I've used a 1 inch piece of PVC pipe with a 90 degree elbow at the base and places the air tubing inside that, approximating the lift tube of an under gravel filter to achieve the same result. Keep in mind that the purpose of the process is to lift water from the bottom of the tank to the top where it exchanges gasses at the surface -- the amount of gas exchange directly between the water and the air bubbles is not significant.> <Which brings me to a WATER pump designed to CIRCULATE the water. In that case you can purchase a very small water pump - like the kind they use in decorative desk fountains even - and place it on the bottom of the tank with any kind of output tube that at least creates ripples on the surface. I use a bigger pump... big enough pump that when it comes time to do the water change, I just add a hose extension to the pump and pump the new water directly into the tank in the next room. To save energy I put it on a timer and it circulates for an hour every 6 - and then on manual for an hour before water change.> <The UP side of the air pump solution is that you are pumping fresh air from outside the container to the inside and need only a small vent hole to allow air to escape. The down side is noise. The UP side to a water pump is less noise and more utility, the down side is that you have to have more venting (to allow fresh air exchange at the surface) which means more evaporation.> Thank you for all your help. <Opinions, yes -- help, you tell me.> James Hall <Regards, Darrel>
Water movement... FW... book time... 10/17/08 I am setting up a 75 gallon freshwater tank and will be using several large power filters. I would like a suggestion on what to use to cause enough water movement at the bottom of the tank to cause the waste to mix with the water so it can be removed by the filter. I know there are air pumps and powerheads all different sizes, but I have no idea what and what size to use. Obviously I want it powerful enough to move the waste but not so much as to cause too much turbulence. <External canister filters are the best filters for large tanks. You can arrange the inlet pipes and outlet spray bars at different ends of the tank, ensuring good circulation. Provided the filter (or filters, added together) give a turnover rate of not less than 4 times the volume of your tank (i.e., 4 x 75 = 300 gallons per hour) and ideally 6+ times the volume of the tank, your filtration system should be fine. Undergravel filters can be good, but again, you'll want a powerhead at each end to ensure good circulation, and these filters are not compatible with sand, plants, or the use of large amounts of rock. Personally, I consider hang-on-the-back filters to be poor choices for various reasons, not least of which is their limited flexibility when it comes to filter media options and the fact the inlet and outlet are close together, making it difficult to ensure thorough circulation. Cheers, Neale.>
re: water movement... abusing WWM If I use only power filters what would you suggest to add for good water circulation? A pump or power head on the bottom? <Properly arranged external canister filters will take care of filtration AND circulation. Much material on WWM about filtration and circulation. Cheers, Neale.>
Re: problem with aquarium system, disease... emphysematosis, induced... no reading 7/8/08 Hi, The system is run by a 1 hp pool pump. <... For this many gallons? Why? You want to read/look into a better, non-high-pressurized pump... this one will "drive you into the poor-house"... See WWM re Pump Selection: Here: http://wetwebmedia.com/ca/volume_3/cav3i2/External Pumps/External_Pumps.htm and the linked files at the bottom> There is a lot of air/water mixing in the strainer chamber so i guess there is pressurized water there. <... yes... this is along with the improper pump, the cause of the trouble here> Is there a possibility of having too much oxygen in the water which is causing "the benz"? <As in Mercedes? Yes> i notice that when the fish were removed they recovered quickly in a medical tank using MelaFix. <... you're joking right? Ridiculous> the water renters the tanks through 1" tubes emptying by the top and there are fine bubbles in the return water into the tank. The bubbles on the fish though are coming through their skin, not attaching to them. The pH is 8.0 (African cichlids) ammonia is 0, nitrite is 0. Thanks! Don <... read here: http://wetwebmedia.com/PondSubWebIndex/PdBblDisease.htm and the linked file related at top. BobF>
Re: problem with aquarium system, disease... emphysematosis, induced... Thanks for all the help! I'm off to shop for a new pump! Don <Ah, good! BobF>