I have 2 of the straight blue and white panels and I have mine 11" above the water. my blues are currently at 100% and the whites are at 40%. Sps
corals are growing pretty quickly, even the ones on the sand bed, so I think I'm going to leave it there. I also have 3 clams on the sand bed that seem to like it right where it's at.
My fans come on as soon as i turn the fixture on at any level. Since these don't get that hot anyway, i don't see a problem with the fan being off at lower settings.