Hey guys so I'm another thread I found out that my powerheads were the cause of my fluctuating water level in my overflow... my tank is a 180g marineland corner flow with a herbie drain. The problem is when I have a vortech pushing flow away or forwards the overflow it will cause the water level to go up and down. Putting the vortechs on the back of the tank will help take care of the fluctuation water level but then I don't get good side to side movement. Anyone ever have this problem?!!? Or anyone with a cornerflo tank what do you do?!