Need help my xina pulsar coral is bleaching

[Nebthet]

Are you talking about Pulsing Xenia?? If so do a small water change and run some carbon. If this just happened after adding the hammer coral then you could be dealing with a bit of chemical warfare aka allelopathy between the two.

Also xenia is one of those types of corals that do well for some and others just can't keep it. Also ensure it is not getting to much light or flow as that will also cause it to recede.