If your copper levels get too high, then yes, you'll have staining issues to deal with. However, I can't say how high is too high. I bought a container of those pucks a couple of summers ago before I realized they had copper in them, and used about 1/3 of the bucket before I realized they had copper in them. No problems in my pool so far....so if there is no other source of copper, I'd say the amount you'll use in a few days shouldn't be a problem.

Janet