I have used, it on two occasions, the first time all the fish in the tank died (2 perc. clowns),but it took me a little to long to get it. Second time, I lot a clown to clownfish disease, and both the yellow tang (first one to show signs of ich, wonder why...) and the other clown made it through, and are still with me.
However, this disease treatment has not been scientifically proven, and I can't comment on how effective I think it is, just sharing my expierience.