Bill is correct that copper is best to treat and that you cannot do it in your reef tank however there are less effective meds you can use in your reef tank. Fish stress can worsen the effects of the parasite and make the fish less able to fight off the parasite. Sometimes if catching the infected bugger becomes a ordeal to get him into the QT and then being in a tight QT is too stressful, he may succumb to the infection. When I had it on my blue tang I tried all "holistic" attempts first knowing that if I had to I could go to QT and Copper. none of them were as effective as copper, but overall I think the combination helped the fish heal thy self. some of these less effective options include hyposalinity, feeding garlic (I made garlic juice in a blender with garlic cloves and selcon and soaked my dehydrated mysis in it and fed it), adjusting tank temp, reducing any stressors, (i.e. fish that they do not get along with, reduced lighting, improving water quality), and adding a "slime coat" additive. My blue tang was able to fight it off eventually. I also used a med called kick-ick which killed my water quality and I am not too sure how much it helped but it was in a tank with just a few cheap corals so I was not too worried about the xenia and GSP at the time. Sorry to hear about your sick fish! Check the RC Archives too there is TONS of info on this parasite from biologists who really know what they are talking about! Its not a new problem!
I think there is a med that you can get if you have a hook up from a vet that treats well too but i dont remember what it is.
