How is your tank set up? FO, FOWLR or a reef
For a reef you might want 20 to 30 times flow. Your filter, protein skimmer and powerheads all count towards your overall gph. If you have a sump you also count the gph of your water pump, although you lose some gph with head pressure (the distance the water has to travel to get back to your tank). Someone on here will have more info.