I have one of those tanks. It came with a nifty 70gph filter that was too big. I picked up this funky Penn-Plax filter that works like a UGF but mounts to the side. Hooked it up to a spare air pump ... works like a charm! Got two bettas in beautifully clear, and amazingly stable water. They spend all there time sparring across the divider, then swim back behind some plants to chill.