First I like to apologise as I sound like an old man already
1. There's two way to deal with ich, one is to just leave it and pray and at the same time feed garlic etc.
2. The other way is hyposalinity or copper.
3. And of course using some unproven reef-safe medication.
Usually some pple try 1. and then wait and wait and the ich gets too serious, by then if the fish still kicking then they try to apply hyposalinity treatment, at that stage already too late. Remember the hyopsalinity do not target the parasites attached to the fish, more parasites will still affect the fish.
So want to use hypo then do it ASAP