Hi there,
Terry is right, copper and hypo is most effective way. QT IS optional, but to be highly recommended. If only as insurance. And they are quite cheap to set up.
I have used Kent RX-P in the past, but not as recommended. I spoke personally to the head biologist in charge of Kent Marine in Europe, and he told me this:
Day 1 - Treat one dose of RX-P
Day 2 - Treat one dose of Poly-Ox
Day 3 - Rest (do nothing)
You HAVE TO HAVE A SKIMMER for this to work. It worked for me, and basically what it does is that RX-P contains an irritive pepper based substance which causes the fish to shed a layer of mucus. With the mucus it will shed the parasite, and on the next day Poly-Ox will help remove the organic material and it contains freshwater plant extract that will sooth the fish (who will be irratated). You may have to do this 3 day cycle a few times to catch the parasite. It worked for me after 2, but 3 months later I had Ich again.
Its not the best way, but if you really want to do it that way, thats how to do it. This wasnt independent advice but it worked in the short term.
Garlic also helps, a natural repellent to Ich and has many vitamins in it.
Good luck,
Tim.