Sometimes I think ich is over rated. It's pretty much in all tanks, and affects fish that are stressed to the point that their immune system doesn't fight hard enough.
I just added a large sailfin tang to my tank last night, by the time I got him home and in the tank, he was covered in ich. My tank is very clean, high oxygen, and lots to eat. Already the ich is all but vanished, and I don't suspect I'll see it again unless I mess something up in the tank.
I don't use QT, I don't treat (we won't get into the garlic thing here
), I just give the fish a healthy, happy home. This approach has worked wonderfully for 10 yrs + now.
If your thought is to use UV to fight ich, IMO, save your money for something else.