You're going to want to know the PAR (Photosynthetically Available Radiation) ratings for different levels of your tank.
In short, it is a great factor in your corals growth, aside from parameters. But for the sake of Google....PAR measures the number of photons of light falling on a given area in a given amount of time.
Try moving them down a little bit. Always start your new corals in the sandbed, and gradually move them up. Examine polyp extension and color as you move them up. When you see good color, and good extension, you know that is the right spot for them. This is acclimation to the light source.