Poly filter will remove copper, but will not tell you if you have copper. Unfortunately, like Lynda said, you may have trace amounts that do not show up on common aquarium tests. call around to the LFS's in your area and see if any of them have a Hanna coper tester.
Another tell-tale sign is you say your growing algae well. Algae will flourish with copper. It's common in fertilizers. |