I have a 55g and am installing a 10 g sump. I have a Amiracle pre filter with a 1 inch discharge, ( it is stated at 600 gph, is this as a gravity feed or pump with a wet/dry filter system), my drop is about 4 ft, so my return is also about 4 ft., what type/size of return pump do I need? I have been looking to the Mag pumps, unless there is a better alternative? As always thanks to all who answer