I have a 36 gallon bowfront and i have decided to put in a 10 gallon sump. I have a 300 gph overflow box and am wondering what size return pump I should go with. I know that it has to be larger than 300 but I'm not sure HOW much. The pump will be around 4 ft below the top of my display tank and i plan on using 3/4" PVC. It's pretty much a straight shot to the top of my tank, only 1 or 2 slight turns.