Swimfins
This is as good as it gets.
Well I saw a beautiful 500g lps and sps reef and the owner (Johnnyrock at Marine supply Canada) could tell you his turnover rate, I'm sure it was at least 30x! I remember the frogspawn getting battered but it looked happy. Turnover is not the most important factor, its direction of flow too. A wavemaker is probably a very good idea for your tank. It prevents dead spots, low flow areas and ensures flow all over the tank.
