I am going to have about +25 times or so, in a mixed reef, 110g. Some SPS tanks have more then twice that. It really depends on what exactly your keeping. Certain SPS demand tons of flow, a lot of LPS don't like thousands of gallons dumping on them. You'll have to modify your flow and placement of corals so that it gives enough flow to the SPS but not too much to the LPS, yet still picks up detris, towards your overflow/skimmer.