What lighting do you have on your tank? Also, I don't think you answered this, but what camera are you using? I am looking for a new camera, mine sucks.
sorry liverock I just now saw your post my lighting is a current usa 2x40w 1 10k & 1 dual actinic my camera is a cannon powershot g1 It does ok for tank shooting but it has way more potental If I could only stick the camera IN the tank