You are asking a question that only you and your tank can answer. Flow is very subjective so it depends on what you and your corals like. The only thing I can offer you is to test different settings until you find the one that you like. Remember that no two tanks are the same so what works for us here may not work for you. Tank dimensions are just a small variable in the entire equation. There is landscaping, type of rock, type of fish, number of corals, type of corals. They all add up to every tank being different than the next one so the only way to really know what works for your tank is to test different settings and see how your corals and fish react.