brain coral/trachy help

[bigblack]

I've got two trachys, wondering what type of light intensity they like, will the be ok under 250 watts mh on the sand, or should they be moved to more shaded outskirt areas of the light where its not so intense. one of them is doing a funny thing when the lights go out it puffs out into a ball about the size of a small orange, and usually it just deflates and looks like a chalice so i'm wondering if its unhappy where i moved it??