I just got two penguin 1140 powerheads each rated for 300 gph. I put them on the sides of my 75 both pointing towards the center of the bottom of the tank. My objective is to eliminate dead spots so that all the waste stays in the water column in order to be picked up by the filters. The rear of my tank is filled with small planter pots...about 18 of them...so that territories can be set up. Please help me decide where the best spots to put these powerheads are....