As with any chelated copper product, you need to make sure you are maintaining the proper levels of copper in your tank.
The manufacturer will state the level and say that you only need to dose every couple days for the first week and then leave it in for a week or whatever (just an example, I'm not 100% sure on the product you have) but if you have activated carbon in your filter, or live rock in your QT, these things will pull the copper from the water. You need to make sure your QT tank is bare bottom and your filter system doesnt have anything that will absorb chemicals. You basically want the tank to be as chemically inert as possible, which a bare glass tank is except the silicone seams, but even those are real slow absorbtion rates.
Anyway, good luck with the copper treatment.