Really there are only two tried and true proven methods to get rid of ich.
Cupramine (Copper based Medicine) It has worked for many, many hobbiest. It needs to be used in conjunction with a copper test. Too much copper and your fish will die, not enough and the ich will survive. So testing is a must to get the right level of copper.
You could also do a hypo treatment and lower the salt. The following is an article on hypo treatment:
Both of these treatments will require you to quarantine all your fish to as big a tank as you can get. The cupramine will rid the fish of ich in about 2 weeks, but the main tank will need to remain fishless for a period of 4 to 6 weeks. 6 weeks in all reality IMO
The following is an article on quarantine tanks and how to set them up:
How many fish do you have?