just so this doesn't turn into some strange discussion of how fish and corals spawn based on the timing and intensity of the moonlight, all of this is BS. I have a Neptune ACIII Pro that will simulate water temp., sun and moon cycles, etc. but really all that amounts to is geeky crap that has no bearing on spawning.
The only real reason to have moonlights over your tank is so that you can enjoy the reef "nightlife". While the cool factor is very high in that I can simulate the light and temp. cycles of the Marshall Islands, spawning has so much more to do wth other environmental elements.