Hi, ever since converting my 125 reef to a 500, i have not been able to keep my xenia. all my other corals are doing fine. they are not growing as quickly as before but atleast they are. my xenia are the only ones that have all died off. actually i have a few pieces left but they went from normal looking to whitish and shriveled up. the others that this happened to died off within a couple of weeks when they shriveled up. the last few have been around for about 3 months and havent died yet. i have plenty of lighting...could i have too much for xenia? my nitrates are a little high but i am trying to do more water changes, just expensive with this size of a tank. i do add iodine and strontium. was never sure if i over dosed so i backed off a bit and it still hasnt helped. any suggestions?