I'm in the process of setting up my 120 4'x2'x2' tank. It has dual corner overflow with a return pump about 1000 gph. I wanted to pick up 1 Coralvue CV-202B dual head (about 24 watts, 12000lph/3000gph water flow), but my buddy said that it may be too strong and may kick around the sand bed. I was going to place it in the back wall middle. He recommended I get the CV-201B dual head (about 12 watts, 6000lph/1500gph water flow). Would having a single stronger powerhead in the middle be good? or should I opt for 2 single powerheads on each side of tank? Coralvue has 750 gph and 1250 gph single heads. The sale ends today and I wanted to pick that up with my MH Lumen bright retrokits. Thanks!