My exp with ich in my reef....
I set up my tank last spring. Kept having reoccuring ich problems. I didnt have the money and space to set up a low salinity tank for 6-8 weeks, so I tried feeding with garlic. I fed with mysis shrimp and garlic paste from the grocery store for a couple of months. By the end of the summer, the Ich was gone and I havent seen it return.
Tank (at the time) was 37 gal with 3 green chromis, a true perc, hawkfish, cleaner shrimp, CBS, pair of peppermints 30+lbs of LR and DSB.
The clown and the chromis's developed ich in reoccuring cycles till the end of the summer and then it just stopped reoccuring.
Hope this helps.
Rob