How long should copper treatment be?

[ag09g]

The title says it all. Currently have two tangs with ich in a 55g quarantine tank. I added the copper today and was hoping to be able to put them in the main tank in a month or so. However I read somewhere on here that there should be a 2-4 week copper treatment and then a 4 week observation period?

I get the copper treatment but why the observation period? If I move them from the quarantine tank into my main tank in a month what are the chances they could still have parasites? My understanding is the copper kills the free swimming parasites before they could reattach to fish. I dont much care if every cyst has ruptured within the tank in the month period, just that the fish themselves cannot carry the parasites into the main tank.

So what do you think, will I be safe adding them to the tank after a month long copper treatment?

 

[Conspiculatus]

Treatment duration depends on water temperature. The higher the water temperature the faster the life cycle.

 

[ag09g]

So if the tank is at 76 degrees how long should it take?