There is a great article (with mostly the same info) in the articles section. I would suggest reading it. It will explain the life cycle of ich and how come you need to treat for longer than most meds normally suggest. And yes, the heat and salt seems to be the least harsh treatment and the most likely to work long term. Clowns are very common carriers of ich, pretty much all of them have it in fish stores. So it is best to treat them before adding to your main tank.
