Need help figuring out whats going on with my elegance corals

[Jamie-Newton]

Hi all ive been having some trouble with my two elegance coral for probably the last 2 months, one i recently bought from an LFS, and the other Ive had for over a year and a half now. Both were doing great and ive never had any issues with the oldest one although the new one has since lost its tentacles it looks like as-well as its colour the larger one followed about a month after.

Both have been dipped and the skeletons inspected and I cant see any issues surrounding pests. All other corals thriving and growing well so I didn't want to disturb them with any changes and hoped the issue would resolve over time with water changes and maintenance. Parameters are also never to out of safe range.

Any advice and help appreciated! photos attached below (they are after lights off although the elegance look the same throughout the day),

 

[Timfish]

I'd guess an issue with your water parameters. Current and historical numbers are needed as well as everything being dosed.