I have about 7200 GPH flow in my tank that is a fish only with live rock. I have two 3200 GPH power heads, one on each side of the tank and about 800 GPH flowing down behind the rock from the sump return. I consider this medium flow for this 210 gallon 6 foot long tank. I guess that comes to just over 34X flow. The only thing I would change is it was possible is to have the same flow with small size power heads.