if you work at the air problem by diverting away some of the air pressure, might help. i'm guessing your air pump doesn't adjust..buy a three-way valve, and cut the hosing to allow a second line to take half of the air pressure away to a diffuser stone that you could hide behind a plant within the tank, creating a curtain of tiny bubbles..you could even use two of these valves and send another line/diffuser stone to the other side of the tank, if it doesn't look to 'hosed-up' for you..
