hi everybody! i just became a member of Aquarium advice yesterday and i wanted to know if you guys could help me... i have a 120 gallon saltwater tank that just started a couple or more months ago. i have a green favia brain coral that is on the bottom of the tank and somewhat on live rock. so its touching sand and rock! but anyway.. it appears that it's 'peeling' its skin and turning brown! is it dying? thanks