I haven't ruled out adding powerheads in the tank at all.... I just wanted to see if it could be done without them...lol I've never seen a large tank without them before so that is why I am trying it.... I have to do everything the hard way. BTW today I am going to put the 3600gph return pump on the tank and remove the mag 8 that was on the "spraybar" So I will see what happens later today...