Corals need light to grow and flourish in your reef aquarium. Once you’ve narrowed down what type of light you’ll use, arranging your corals based on the chosen lights will determine if they thrive or fail. Keep in mind, each lighting style: LED, compact fluorescent, metal halides and T5 fixtures has pros and cons, and corals respond differently to each.
Initially, you should start with lower light in the center and move your corals slowly as you observe how they adjust to the different sections of the aquarium.
Metal halides grow SPS (small polyp) corals quickly, but take care not to have the high intensity versions as they can also burn your corals. SPS can be placed middle to top of the tank whereas LPS (large fleshy corals) should be with the soft corals at the bottom.
While fading in popularity, CFLs do allow you to place your LPS and soft coral anywhere in the tank. The downside with compact fluorescents is that they do not grow SPS corals.
Since the quality of LED lighting can vary, be sure to use high quality LED, which brings out the colors of your corals. Most LEDs can be adjusted in strength. With LEDs, SPS corals should be at the top, LPS in the middle and soft corals at the bottom.