Mobile Bay Reef Keepers

how much flow do i need in a 30 gal tank not alot in it i have a star polyp but not doing very well and a few snake polyps and 3 fish i was going to buy a Hydor Koralia 2 but not sure if i need 1 or mabey 2 any ideas im so

That would be fine. You may even find that you need 2 Koralia 2s for decent flow. You would have to play around with 2 of them to keep everything in place/happy, but I think that may work better for you.