My pulsing Xenia is letting out smokey stuff and then there's also like stringy stuff coming out too. Is this bad?
If it is falling off the frag after five days, something is wrong. What are your parameters? Alk in particular.
Xenia reattaches itself a day or two after being cut. Unless it is a very large piece, do not worry about it hurting your other corals even if it is dying.
I have plenty if you need more. Start with your parameters. I find my Xenia is the first to show stress with alk swings.