Every reef safe ich treatment I've ever seen noted has been snake oil. There are some good stickies in the disease treatment forum on the life cyle of ich and how to treat it.
I think you'll find that you'll end up spending enough money on reef safe treatments and livestock losses to easily have bought a HT, especially if you look used on craigslist or the like. Beyond that, your HT will in the future allow you to QT all incoming fish, preventing the problem in the future.
Good luck.