Lights on for how long ?

[FitoPharmer]

too much light depends on what your keeping and your tank. Too much light usually means too much heat, that will kill corals. But corals can also be killed from just too much light (bleaching by either intensity or duration) the symbiotic algae inside the coral can no longer take the conditions. If your corals are looking good, growing, and color is usually a good sign, your light is not too strong or on too long. Given enough time and the right conditions, it is crazy how much corals can adapt to light changes.