I have a question about this as well. The NC28 just has 2 starlight leds and the vague instructions say to leave them on all the time. Late at night when I look at the tank it seems super bright and I've noticed my clowns hide in shadows. One always stays under my return duckbill and the other hides under the MP10 wetside. Granted, on the reef there is rarely pitch black, but I am wondering if the starlight may also be adding to algae growth to some degree. What is the consensus on a preiod of full black at night? I've thought about putting some sort of filter on the leds because they truly light my whole basement with light you can read by. My corals don't have any sort of consensus in being open or closed, they all seem to have their own schedule.
oh, and my frogspawn ONLY closes if it gets touched. If they're supposed to close, then it's the lights.