I used Kick Ich twice first time it worked great. Second time killed all but three fish, but soft corals (all I had at the time) did fine in both cases. The company suggested it has a shelf life.
If you don't want to do the quarantine/fallow thing (best option) you could get a couple cleaner shrimp and/or two neon gobies (2 because they will get ich too but can clean each other), and lower the temp below 80F say 78degF. Above 80F the ich life cycle is continuous. Below 80 not all the cysts that drop off and form eggs will hatch, but they will still be in your tank waiting for a warm day. (that is why lower SG and warm up works, it hatches the things to death). Siphoning the bottom and regualr water changes with the above can get a strong fish through, but you'll probably loose 1 or 2.