Ok I need some advice on my closed loop. Right now I have three returns coming out of the back wall of my tank, and two returns from my sump on the top of the tank. Im thinking of turning the top two returns into my closed loop, adding 4 more, and a 1" SCWD like the picture below. I know I'm gonna need more flow for sps. I dont want my sand to be stirring around a lot though. I would like to try to avoid powerheads if possible. Im running a gen-x 40 pump as my closed loop now but im gonna upgrade and use that as my return for the sump What size pump should I use that will give me plenty of flow for sps but isnt gonna cause a sandstorm.