Chalice has always done really well and was grown from a small frag into this with high NO3 around 25 but now he is really struggling checked NO3 and its crept up to 50 trying my best to reduce, but is this the reason for the melting I did catch my yellow tang pecking at the damaged areas so moved the coral to the sump ,for protection to recover ,do I cut off the damaged areas (whats the best tool to use ) all other LPS seem to be doing well blast doing really well . Experienced opinions, please .