Tracey trouble

[reefteaser]

I’ve had this coral for a few years. Many month ago, it started deteriorating (along with a few others) when my chemistry went out of whack. All is well now, and my other corals look great, but very slowly over time this Tracey has lost some tissue and some of the skeleton has algae growing on it. It’s been this way for quite a while, neither getting better nor worse. What can I do to improve it? Can the bad sections be cut away without harming the coral? Can it be fragged?
Appreciate any help from those familiar with this (former) beauty.

 

[reefteaser]

Oops, forgot to attach.