I have had these about three weeks and they do not seem to be opening up like they used to. I have them in a 75 gallon tank with 192 watt power compacts. They are in the center of the tank in the sand bed. It looks like the ones on the sides and the ones that are shaded look and open up the best. The ones that are in the shade look to be the brightest color. Should I move them to a more shaded part of the tank? I have read that they need light? There is hair algae growing on the very top of the rock and is almost starting to cover them. Any suggestions?