How big is the QT again? I've got a 20g with 4 tangs in it and I change every other day. I think that would be a good schedule for you at first, then after a couple of weeks, look at the levels after 2 days and see if you can go a 3rd. I would also get rid of any bio-wheel ont he filter or carbon bag filter as they will suck out the medicine (the carbon bag will, not the wheel). Replace the wheel witha sponge that's been sitting in your sump for a week or so, that will help keep the ammonia down. I wouldn't add chemicals to the QTto try to balance the levels. It's easier doing PWC's than monitoring levels with chemicals. Plus the tang will be stressed already with the move and all. Be sure there is nothing porous in the tank. Don't give the parasites anyplace to hang out if not on the fish. Also try to keep lighting to a minimum. Beside the natural sunlight in my living room, I only turn the flourecent lights on for about an hour at night, but I do keep it next to my big tank so it does get some light from the main tank.
I usually just let them fight it off and it works unless it is a really bad case, but in this case i just dont know.
