Everyone has an opinion on this. If you read about all the science, triggerdood has the best answer to get rid of the cysts.
Is it the best answer for your situation? How big is your display? How much money do you have to fix the problem? If your displays is only 30 gallons you might be better off taking everything out of it and starting off with some new rock from a display that you know is ich free. QT your old live rock in a large plastic container with a heater and a pump for the 91 days and do the total tank transfer method with your fish.
If you don't have the time or money to do all that the best thing might be to do would be to get a QT set up. Qt setup with 2 10 gallon tanks and 2 qt heaters, pumps or air pumps with extra line and air stones and just do the total tank transfer with your fish. Get your fish free of any active cyst on their body. Feed them with a high-protein food soaked in selcon. Make sure you keep the QT tank clean so you don't get an ammonia spike.
To be completely free you need a lot of equipment tanks, pumps, heaters. You will need to do a lot of work testing, water changes, moving your livestock.
What's best for you is what's really important, so that you enjoy what you're doing.
I would avoid the copper. Once you do copper you may always have a problem with any of equipment used with copper.