How can I determine if my corals are receiving excessive or insufficient lighting?

Always remember to keep an eye on your corals once you make any changes to your lights. Corals are living animals, and they will respond to too much or too little light, sometimes in immediate and easy-to-spot ways. Below is a table with some common coral reactions to too little or too much light- or just enough.
Note: Bleaching and browning are progressive symptoms, meaning they happen over time. It takes at least several days for browning to occur, bleaching can happen in about 1-2 days. If you stick to the acclimation schedule your corals should not suffer any adverse effects. However, if you increase the light output by too much or too little, the symptoms laid out in this chart can help determine what adjustments must be made.