Tank transfer method in my opinion should be used as a secondary option on top of a primary course of action for treatment. Because there is a cycle where these parasites attach, detach, reproduce and reattach it is hard to get them all at the right stages. Plus you may not be able to see them on the fish but they may be deep embedded in the fishes gills. I recommend looking here for another treatment option. Copper is really difficult as there is a very small therapeautic window that is safe for the fish but also effective against the parasite. Copper also cannot be used on angel fish and should only be used in QT tank. Keep in mind live rock and ceramic decorations absorb copper which makes it less effective. There are a few other treatments you can try that may work better in the sense that it is less harsh on the fish. I love this website as it has a lot of detailed information on treating fish disease and preventing disease. They also sell most of the medications they talk about on this website which makes it really easy to read up on it and purchase rather than jump from site to site looking for them. Definitely recommend keeping an arsenal of these medications so that when disease does come about, you will be more than prepared.
http://www.americanaquariumproducts.com/Aquarium_Ich.html