Confused about GSP

yeah, it was attached to a live rock. Looked really nice at the store until I got it home lol. I accumilated it just like my other corals. Maybe I should have done it better. Ah well. I am going to leave it in the tank and see what happens. I am about to order new lights for my hood as I noticed half does not work, along with the life of a compact flour. Its only 2-3 months old but I can tell its fading. Maybe that will help some. Thanks though for everyone input. Just wasnt sure what a dying/ dead coral would look like or what it goes through.