There are a couple of people here who swear by using salt (including reg table salt) for treating ich but I have to tell you I recently treated 3 seperate tanks, 5 gal and 2 30 gals. The 5 gal was a work friends and we used salt and heat...all inhabitants died including the plants.
Both of my 30 gals got ich (long story there...) and I was afraid to use salt or meds because of my catfish and snails so I decided to try heat only first to see if might work. I'm happy to report that it's been 2 weeks since the last spot disappeared and I didn't have a single loss.
