There are a number of ways to treat ick. I'm sure you studdied up on them all. I personally try to remove any stress factors and let it run it's course. It does have roughly a 30 day life cycle, but I've found that allowing the fish's immune system to take care of it seems to work in most cases.
Of course the best method is to avoid specamins that look stressed or sick. Then Quarrantine them for at least 30 days before adding them to your main system. If they do get sick, wait 30 days after symptoms disappear to transfer them.