Posted: Thu May 12, 2005 3:21 pm
Welcome. How big are your RES? By "outer" do you mean a canister filter? If so, the ones I can think of would be too powerful for a 20-gallon tank. (But if you were to go with a bigger tank...)
The one 20-gallon tank I'm using has a Fluval 2+ in it, which is not adequate. (And you did say you have a Fluval 2 in a 10-gallon.)
Others will no doubt have their recommendations (I'd first recommend that bigger tank), but I've heard some positive things about Whispers and Aqua-Clears. Perhaps if you asked about specific brands in the Equipment Forum, you'd get a better response.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-