Just out of curiosity, did you buy a PAR meter? I was thinking about renting one from BRS after I get the new lighting. It seemed to be quite a large cost for something I would likely only use once. Next time I do an ICP test, I am going to get two test kits. I want to see the results immediately before and the day after my regular water change. I am extremely curious to see what happens to the trace elements. One of the guys at WWC told me to check my Iodine if everything else looks good, but I am still losing Xenia.I need to do another ICP just to check on things. One thing that I've found is light intensity can make a big difference especially if everything else is not perfect. One of the best things I ever did was to get a Par meter and measure all possible coral placement spots at different intensities and record the results. This should help me to place corals better moving forward and set my lights correctly. This is where I recorded the results.
After reading how Blastos like very low light I found a spot on the sand under an overhang that seems to have made them very happy.
My understanding is pulsing Xenia can adapt to a variety lighting so your lights may or may not be the issue. It would be interesting to see the results of the ICP if you post them.