# filtration rule



## Kimmah (Dec 26, 2011)

how many times should the volume of water be filtered over an hour for a mbuna tank? I have read and heard of lots of different rates and am confused as to whether I need to buy another filter or not. I currently have a 1000L/hr filter for a 450L tank. Thanks.


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## prov356 (Sep 20, 2006)

For biological filtration, that turnover rate is fine. Just make sure you're getting enough circulation to keep the water well oxygenated. Add an internal circulation pump, if needed, and it probably is. Combine with adequate water changes, and it'll be good.

General tank turnover rules aren't helpful and I'd ignore them. They're just numbers pulled out of the air that mean little on their own. Filters with higher gph will do a better job of mechanical filtration, but vacuuming can accomplish that also. Bio needs little 'turnover'. You need circulation to encourage adequate gas exchange. Surface ripple can asist that gas exchange, CO2 out, O2 in. I prefer to look at the individual components of filtration and water quality rather than suggest some arbitrary 'turnover rate'. How do you rate the turnover of sponge filters?

Something like a turnover rate might be helpful if you're only going to put one filter on a tank and need some guideline when sizing it. But I wouldn't just set it up and be satisfied because the turnover rate is good. I'd use a spray bar at one end with the intake at the other, so you're getting good circulation and some surface ripple. Point is, same gph filter that's set up differently can result in differing levels of water quality. Look beyond 'turnover rate'.


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## lucid_eye (Apr 12, 2009)

Very well said Prov. I personally go with a three headed approach. two slow flow biological filter than can each handle the volume of the tank alone. Two mechanical filters that can handle tank volume alone. And 3-4 additional powerheads to disturb the surface/keep the substrate clean. This is the practice I try to follow and then I always end up buying extra canister filters I don't need and find a place to shove them under the tank. Granted I am talking about 100-300 gallon tanks.


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## tim_s (Nov 27, 2011)

Hi,

I think a lot of good advice has already been provided but for myself my general rule is double the recommended requirement.

I.e.if I have a 200 G US tank I want the water being moved at 400 GPH but this is a personal thing, and if I can afford it - go bigger.

Example: On my 90 G I have an Eheim Pro 3 XL for 300 GPH tank with the spray bar pointed up-wards moving the water length wise down the tank, however, I also have 4 air-pumps running but I think this is to benefit my concerns as I am sure my water has reached it's maximum oxygen retention point.


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## 13razorbackfan (Sep 28, 2011)

I personally like 10 times filtration per hour in filters that do both mech/bio filtration.

I actually have even more in total water turnover which includes my power heads.


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## PfunMo (Jul 30, 2009)

Some logic is often missing in this discussion. If your tank water is being turned over 2 times and all ammonia and nitrite are being turned to nitrate with the water as clear as you want, what is the possible logic of having the water turn over 5,10 ore even more times? The filters are only going to remove the waste they find, If they are dealling with it, adding more filters is just folly that produces more expense, noise and work. If your filters are not doing the job, you need to add more but just adding more to meet some "magic" figure is simply being mislead and foolish.

Test first and then decide before buying the hype!!!


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## Kimmah (Dec 26, 2011)

Thanks heaps for all your help everybody. You have made this topic more easy to understand


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## jwmachon (Dec 29, 2011)

Mmm can't believe how helpful u guys are thanks alot, I'm going throw a spanner in the works, how about 2x fluval g6's


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