"I have two Red-Eared Sliders and they can produce quite a bit of waste, but the filter is great and powerful enough for the 20 gallons they swim in. I do recommend however, some sort of air pump/bubbles to help with water circulation if your tank is large (mine is a 40 gallon tank.) The filter media though is affordable enough to simply replace it after a while instead of trying to wash it all over and over again."