amason, again, I'm not Beth, but will chime in...
If he has what appear to be raised grains of salt it is probably ich. If you already have him in the QT you might as well go thru with hyposalinity. It won't hurt him and if it is ich it will clear it up. You will need to lower your salinity to 14 ppt in about 48 hours and then start counting down the 4 weeks once the spots are visibly gone.
Remember, just putting him the QT will not cure him unless you either hypo or medicate.
Did you check out the threads at the top of this forum? There are pictures of ich and very good instructions on treatments. Also look at the thread in this forum regarding the Powder Blue Tang. Very good example of what ich looks like.
Good luck!