[Myka]

I prefer 6-7x per hour turnover through the sump.

I like LPS corals, and they don't like high flow from the powerheads. BUT, the turnover rate from powerheads is VERY different if you're using propeller powerheads (like Tunze and Koralia or MJ mods). You can go about 2x the turnover from propeller PHs versus impeller PHs.

I like about 10x per hour turnover from impeller powerheads, or about 20x turnover from propeller PHs.