Unfortunately all the best methods involve a quarantine tank, unless you are running FOWLR. Copper and Hypo-salinity are the best treatments, along with leaving you DT fallow for 6 to 8 weeks while all the ich in there dies off as well. Other than that, take a good hard look at your tank and it's inhabits, if they are coming down with ich, it's due to stress of some sort. Stress lowers the immune system making your fish more susceptible, allowing them to become infected.
And just FYI, most medications that are "reef safe" are worthless.