I had an ich outbreak in my 400 gallon DT back in September. I drained it and removed all my live rock (525 lbs) in order to catch my fish that were then moved to a hospital tank. I treated with Cupramine for the first 4 weeks in the HT, then iI kept the fish in there without any signs of disease for the next 4 weeks,. When they finally went back into my DT, guess what- the ich came back after about 2-3 weeks. Even when my DT was fallow, I was still running 2 Emporer Aquatics high output 80W UV sterilzers.
I am beginning to wonder whether your tank can ever be "ich free" as so many people on these boards say. I know is is a controversial issue. It makes sense to that that should be the case, but it never happened in my case.
I now just soak all my food in garlc and selcon and am watching the spots. My fish are active, eating well and behaving normally with the ich. Should the ich ever start to overewhelm my fish I will treat my entire DT with Cupramine including the live rock. Most people wil say that that is a terrible idea and I am not recoomending that you do this. My tank is a FOWLR . and there are some people on these boards that have doneexactly that sucessfully.
Good luck. My only real advice is to not waste your money on any of the so called "reef-safe" medications. Very few people would argue that those don't work and are a waste of money. If you decide to treat, hypo or copper are the only real options.