What happen to my sps?

[jason604]

I got my blue German last week but it was too big to be placed on my rocks so I left it on my sand bed till I had time to move things around n yesterday I notice a huge area of its center RTN. Is this because I left it on sand bed for too long? I fragged a bunch if pieces off it on day 1 and this is also on sand bed but it shows no signs of damage at all. Should I chop up my huge colony or leave it as is and let it encrust the dead part over time ? I really prefer to keep it as 1 big colony if possible =(