Xenia is a fickle coral to grow, it seems to either love you or hate you. i cannto get it to grow at all in my tanks. test all of your parameters , check your lighting, and look at the Posphate level if possibleand maybe change out the carbon. ( possible chemical warfare withother corals)
the hair, need to do a really good cleaning, do some
wet skimming and figure out where it is gettign extra food from, if you have not, try and geta few turbo snails, they do wonders on hair algae, one thing you cvan do is try usinga pair of tweezers to remove it if it is in a place you cannto get to easily
