Ultimately, the question of flow is going to come down to what corals you keep. SPS like higher flow (but not direct high flow) whereas octospawns and froggers tend to like gentle flow. If you get good, random currents in your system and alleviate the dead spots where detritus might build up, it will ultimately depend on what you are trying to keep and those corals will 'tell you' if it is too much or not enough based on their reaction. Sorry that my comment is about as useful as wet toilet paper after food poisoning...but in the end, it all depends.
