AnnaMNR 68 Posted July 28, 2013 I want to know if I have to buy another filter, and if so, what size? The one I have now is a 90 gallon 0 Quote Share this post Link to post Share on other sites
sarajo 566 Posted July 28, 2013 (edited) It's recommended to have 10x the turnover rate for goldfish so 550 gph for your 55 gallon tank. A lot of us here including myself also prefer to run 2 filters in case one breaks. If the filter you have now is not causing any problems in your tank and you only have the one fish, I think you could get away with it let's see what others have to say as well. What type of filter are you using? Edited July 28, 2013 by sarajo 0 Quote Share this post Link to post Share on other sites
dnalex 13,633 Posted July 28, 2013 I want to know if I have to buy another filter, and if so, what size? The one I have now is a 90 gallon As Sara Jo asked, what filter are you using? The normal recommended filtration rate for aquariums is 7.5x-10x+, but this will also depend on your set up, stocking, and type of filter being used. 0 Quote Share this post Link to post Share on other sites
DieselPlower 2,123 Posted July 28, 2013 I agree with the 10x for a fully stocked tank. I think I would want 2 filters on a 55 gallon anyway due to the length of the tank. The side without the filter wouldn't have much flow at all. 0 Quote Share this post Link to post Share on other sites