The temp may be the prob, but I am not sure if 82 is high enough to stunt its growth. I just know that temps that other corals do fine in the xenia will melt down in. They are normally the first to go if you have a temp spike.
I am assuming you also have very strong lighting, and the water temperature is a bit on the cooler side(under 80 degrees)?? Xenias needing high alkalinity is a myth in my book. I keep my alk and calcium at 7-8dKH and 450ppm respectively, but xenia do best in cooler waters and intense lighting...
