I use heat/salt as well. No need to use medications, thats how you kill fish....
I think the heat is the key, the salt plays a minor role.
I raise the temperature up to
AT LEAST 87F over a few hours. You don't have to do it over a couple days like some people say, never hurt my fish. Add salt gradually over a couple days until you have the equivalent of 0.5 tablespoon per gallon, anything more seems like your making brine.
Leave it like this until all the ich is no longer visible on the fish. Then maintain it for
another 10 days. This should get rid of it. I think the problem with ich is people don't treat long enough and thats why it returns.
Best of luck!!
Burt