Sanjay did some LED tests this year and last.
Cloud cover does nothing for the coral which is why I just use the set points to mimic the sun intensity through the day.
I don't care about the coral*, I'm just looking for lighting effects.
(*I mean I do care about the coral, but I just thought it would look cool to show clouds... It would be even more awesome if the lights would brighten in a wave so it looked as if the clouds were moving!)