I have a 200 gal (7x2x2) and a 50gal sump (~20 gal full). I use a Mag 12 that puts out about 1200 gph with 2 ft of head and an eshopps PF-1200 overflow rated at 1000 gph. I use some of the excess flow from the pump to go through a 36W UV sterilizer and algae scrubber.