# Enough GPH for my tank?



## Abb (Mar 7, 2009)

I have a 75 gallon, planted tank with a few fish. Small biomass. I Was wondering if a 250 GPH Canister would be okay. Need some input


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## overleaf (Feb 1, 2009)

That would cycle the tank 3 times per hour... that's considered a little on the low side. Ideally you'd want 5-7 times. That means 2 of them would be up to the job


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## BillD (Jun 5, 2006)

The only way to know for sure would be to run it and check to see that the ammonia and nitrites were at zero, once cycled. A planted tank, tends to need less filtration than a fish only tank. If you frequent aquarium forums, you will soon discover that almost everyone knows more about filtration than the manufacturers of said filters. If you look at how little water a sponge filter moves, while still providing sufficient filtration, you really have to question the high flow/turnover rates many advocate. In addition, every solid surface in the tank will get covered with nitrifying bacteria and becomes part of the total filtration.


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## fishman2 (Oct 10, 2008)

I would recommend that you test the water parameters in the tank and then the output water from the filter. This will give you an indication if your filter can provide you with the biological filtration you need.(The readings will vary day by day until your tank has cycled)

Turn over rate has nothing to do with filter efficiency, as was just mentioned.


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## planter (Jun 9, 2008)

Canisters generally run with a low GPH rate then HOB's. The main reason for this is that it takes much longer for the canisters clog over time and the motors on the canisters will still push a good amount of water even if it is a little more clogged up. The HOB's GPH drops much faster and clogs much easier then a canister meaning that it's very important to keep that filter clean all of the time. Which results in the BB loss more frequently. There is also much more media in a canister that is not disturbed as much. This allows the bacteria to stay at a stable population over a longer period of time. 

A canister with a rating that high like a 2217 for example has a GPH rating of 265 gallons per hour should be enough for tank that size with a light bio load. 

Bio load IMO should be the main concern when it comes to filtration. if you stock a 30 gallon with the same amount of fish as a 60 gallon same kind of fish will produce the same amount of ammonia. Both should be filtered with a filter that can handle that same amount of bio load. Unless the filter is used for specific purpose that is what needs to be considered.


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