12" from water? IMO this canopy has the perfect height for the lights, 12 away is a little bit to high, most light loving corals you try and place higher up to get as close to the lights as possible.
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My fans blow across the tank from back to front, thats why I have the washers mounted on front of the tank, the hot air blows across and then down the front of the tank, I also have a ceiling fan thats aimed at the back wall to supply fresh air to the back of the tank, even with 3x250 and 4x96 my temp stays at 79 with maybe +- of .2