not to get too far off subject, but your tank is similar in size to mine 180 to 120... I think you are 6 foot and mine is 4 with all other dimensions the same... 2 foot by 2 foot? Anyways, how do you have your rock setup? I built a huge mound in the middle about 15 inches high that would pretty much be the same if you looked at it from behind. Since the fish dont even use the space in the back, I thought about filling in the back with rock (which would have to be right up against the glass), and make it sort of a rock wall that ascends to the back corner of the tank. But then I dont know what to do with my powerheads. Your tank just seems to have the rock utilized much better than mine does.