Question. I got a 120 gallon tank that I just lately convert to a saltwater tank. Im having trouble trying to figure out how much GPH i need and where do i need it to come from (either the return pump or power heads or both and if both what should each one be rated at). I tried to run a return pump that is rated at 1300 gph from 6ft, but it seem to be to much. It was mixing up my substrate and making my tank cloud. Right now I put a pump that is rated at 200 gph in the sump for now. I want to buy another pump, but i cant figure out what rating i should get. Can someone please help me?