ICH Help

[dickey23]

I currently have a 55 gallon that I purchased as an established tank that was in operation from Craigs List. I yellow tang, blue tang, clown, scooter blenny (now dead), royal gramma, live rock and sand and couple extras like feather duster, leather, etc. I have added fish, most of shich have died for one reason or another. The biggest problem is ICH. I have lost some nice angel fish costing me over a couple hundred total in fish. I have used stop parasite as recommended by the fish store. It was labeled "reef safe". I have read copper is really the only treatment to kill this stuff and then was told that I can't use it in a reef set-up.
I have also read I need a QT Tank and I do not have one. I guess I need something like one of those Nano Cubes or something.
All my fish are fine and living well but everytime I have put a new fish into my tank, a couple weeks later they get the white spots and die. I try to treat with the parasite stop and it really has not saved any fish to date other than maybe the ones already living in the tank. PLUS all of a sudden my bulb anemome got small and started looking like it is dying. It even moved around the tank, which it has not done in months.
Can anyone help with suggestions to kill off the ICH. I don't want the fish I have left to die even though they have been doing well.
Alot of people seem to talk about Garlic but is that just a temp solution or does that just help when they are actaully infected and it acts more like a medicine.
I have read a lot online but there seems to be a lot of disagreement about this issue.