I'm not so worried about the heat at long as I did not put to many lights in, I think it would just keep my heater from turning on (I'd probably only worry about it in July and August, but I could by way off on that) I'm not opposed to cleaning the light from time to time, and wonder if the coralline would grow on the hot led. I know water creates a different type of light angle, but I was under the impression that the surface reduced the light significantly and it would make since to me with how much reflection power water has. I guess I'm looking for specific numbers on how much light is lost when passing through the surface of water.