Capn, (I am also a Captain) ich is a pet peeve of mine and I have been dealing with it since the fiftees. There are all sorts of ways of controlling it and just as many ways that people use that don't work. Cleaner shrimp is my favorite, next is a uv sterilizer then we get to garlic. I feed my fish garlic because I feed them all sorts of things. I feel that it will do nothing for ich. But since I am not the God of ich I won't tell people not to use it.
I do know the fastest way to cure ich is with copper, formalin and quinicrine hydrocloride all used at the same time. (I think I invented this combination) You will get a cure in about 24 hours. You will still need to keep the fish medicated for ten days to kill all the paracites in all of their stages.
Unfortunately, this can not be done in a reef. The quinicrine alone will kill ich and can be used with some inverts but it is no where as good as copper. If it were not for copper there would not be a salt water fish hobby. If your LFS tells you that copper was not used on his fish he is probably un informed. Before we had copper, most of the fish would die in a few days in the store. I know because I helped start one of the largest aquarium stores in NY in the late sixtees. Copper will not ruin the fish liver or do anything else that is detrimental to the fish but ich will. I used to keep copper in my tank for years, we had to because all fish were shipped full of ich. As soon as the copper disapated, ich would appear. We diden't quarantine anything.
If you overdose copper you will kill the fish, if you overdose any good medication, you will kill the fish. Aspirin will kill you if overdosed.
Hypo will also kill ich but sometimes the fish will not live long enough for the hypo to work.
There is no medication for ich that can be used in a reef that will work. I wish there were.
Have a great day.
Paul