I get Coral Magazine (great magazine BTW) (not too technical, not too general) and one author mentioned he felt that his tank should never be completely dark; that fish can/do run into things in complete darkness and that the ocean is never in total darkness except in very deep waters. I found that "interesting," but not necessarily the reason I want to add lunars. Nor is fish spawning; I have a clown pair that lay eggs 2 x a month. Since it's a reef tank, I'm thinking about the corals more than the fish. Moon light is a natural thing for a lot of corals. I'd like to see examples of blue and white lunars, if anyone can post photos or direct me to photo samples. Ebay has some but they just don't look "realistic". JKJ