I'd put my sps growth and condition up against anyones and I've got thriving xenia colonies. So don't tell me Layton, that xenia don't thrive in the same conditions sps do.
I have read that when xenia crashes it can be a good indication of a problem, and also that they pulse more in lower nutrient tanks to facilitate nutrient uptake, and pulse less in higher nutrient tanks cause they dont need to to get the supply of nutrients.