Hi. I've been adding some proteam every few weeks at the advice of the person who services my pool, in an effort to avoid some possible black algae. It seems as though every time I add it, I get a black ring in my skimmers. I also take my water twice monthly to the pool store for a sanity check and it shows copper (.4/.5) . I've looked everywhere and I don't see that polyquat 60 contains copper, but am I missing something? Thanks in advance!