BeanAnimal
Premium Member
It is believed that corals as a photosynthetic colony can only use so much before it is just there in excess.
Well it is not "just there in excess" like a spare burger that nobody wants to eat. At some point of over exposure, the corals become photoinhibited. That is, too much light and they coral may either shut down for protection or become damages. In minor cases, the coral is unhappy after it has been photo saturated for too long. This may affect growth and/or looks. in more severe cases the zooxanthellae may bail out to get away from the light (coral "bleaching").