Fromia star dying?

For the past few weeks my fromia stars legs look like they are withering away. I first assumed something was pecking him so i moved him into the refugium but its getting worse. I found alot of conflicting info on the net about the cause, could it be shock from ph/oxygen changes, is it starving? Theres in plenty to graze on in the fuge and it gets more than enough light, but also has some rock to hide in to escape the light. Not sure what the next move is, any suggestions?