I agree with TKOS. I like the salting method with offer no introduction of chemicals to the tank. I have used other treatments and have gottne good results, but, as TKOS points out, just because the white spots are gone does not mean that ich is gone. Follow the full treatment lenght of 2-3 weeks and in the end your fish will be happier and healthier. There is alot less stress this way.
Good Luck with whatever method you choose.
Good Luck with whatever method you choose.