Alot of people that have sps dont now how much flow thay need . So im going to tell you 60 to 80 turn over is just right for sps. Now how do i now how much turn over is in my DT, Its very simple add up all you PH in you dt tank and return the return is trick so say you have a mag 9.5 with 3/4 pvc and its about 4 feet up to Dt , you will average about 700gph so add all the Ph and return pump and divid it buy your DT gallons For example this is from my tank Ph 1200gph + PH 1200 gph+ wavebox 5000 gph + return pump 700gph = 8100 gph Dividid bye 120g = 67.5 turn over in display tank.