Turning off the light will definitely help.. as far as Dinos not killing corals.. I watched with my own eyes about $10,000 worth of frags get "smothered" to death from dinos, they can most certainly kill SPS corals. Not by attacking/poisoning the corals, but by smothering/irritating them so the polyps don't come out, zoox expels from the corals (bleaching out), and given just a little time, since polyps won't come out, it can't feed and it dies.