Are you using UGF only on your FOWLR? I wouldn't suggest that. You'll get "dead spots" under the rock. Always use more than one type of filter, if something happens to 1 then you've only lost half instead of all. I would add some kind of outside filter. I'd also go with RFUGF. If you dont have that kind of set up it's easy to convert. Get the foam strainer cartridge that goes on a Hagen pond pump and put that on the intake. Cut the UGf tubes above the water line and run a piece of hosing from the maxi jet out down it. Have the strainer cart as close to the top of the water as possible.