Do you have a stick-on ammonia alert gizmo (Wal-Mart)? Most ammonia tests don't work with Cu and ammonia-neutralizers (Prime, amquel, etc) are deadly when used with Cu. If your filter was well-seeded, it should control ammonia. Until you have a test kit that is compatible with Cu, I wouldn't change water unless ammonia was rising. You can tell a lot about copper and ammonia levels by just watching the fish. if they're eating, not gasping for breath, or breathing heavily---they're OK. Cu does say 2 weeks, but that isn't enough. I suggest 4 weeks with a CU level of .35-.40 (less than the bottle suggests. ) If things go south before you can be sure of Cu level; then do a big WC, run carbon, and start over when you have the right tests. If you know ammonia is a problem; do a WC with new water at the same level of Cu as that that is removed. I'd wait with the popeye treatment too.