I had to resort to the freshwater dip for a yellow tang that I had when I first started my tank. My tang developed "cloudy eye" and the only way I could medicate him was to dip him. I didn't have a qt tank at the time but I have one now. I didn't choose to do the 100% fresh water dip, instead, I did a half fresh and half sat water dip with Formalin 3 added. I can't remember how long I dipped him for at a time, I think it was 10-15 min. I monitered him for signs of stress and he seemed to do fine. I dipped him three times over the course of 4 or 5 days and it all cleared up!
Now, Im not exactly endorsing this method, but I was in a bind and didn't have a QT tank set up. I would suggest using a QT tank at all times if it is at all possible. I hated having to stress the little guy out by netting him, dumping him in the bucket, netting him again, and dumping him back in the tank. My poor clowns didn't know what the hell was happening to him!
Im sure he had an adventure story to tell them everytime he got dumped in again!