Posted: Wed Dec 21, 2016 10:46 pm Re: Filter on 120 gallon tank
Those gallon ratings are for tanks filled with fish. Turtles produce lots more waste than fish. I'd say something like an FX6 is what you need to have for a 120 gallon tank. I ran one on a 55 gallon until I upgraded the tank to a 150.
Tobi a RES born in 2012
1 dog, 1 teenager, 3 aquariums filled with fish, snails, shrimp and a bit of algae