First, you need to get a copper test kit, you can't treat with copper unless you're treating at the correct dosage and time, also too high of a level can kill the fish, so you need a copper test kit to check the level.
Start the dosage slowly and bring it up to 2.5 - 3.0 over a day or so. So now dose about 1/3 the recommend amount, then tomorrow morning another 1/3 and then in the evening, after checking the copper level, keep dosing until you bring it up to at least 2.5. You then need to treat for 2 weeks after the last spot you see on the fish. It's best to treat from 4 weeks.
The great thing about Copper Power is that you can treat at very high levels, almost 6.0, without stressing, or killing, the fish.
If you plan on treating them in a QT, which will now be a Hospital tank, you need to make sure you have bacteria media in there to control the ammonia and nitrites. Also, you don't want to feed that much if possible. When you do water changes you need to retest and make sure that you're still at least 2.5, otherwise the copper isn't going to work.