So, discovered this by chance. For the past several months my bathroom toilet will get a mysterious blue ring around the inside of the bowl. Family accused me of pouring chemicals in the toilet but the only thing I dump is water from water changes, never straight chemicals. I finally got curious and looked up the reason and... lo and behold, a blue ring can be caused by elevated levels of copper. I do not have a copper test kit, so I have not been able to test my water. This has not been an issue (the blue ring) until a few months ago. I am on a well that has never had issues before to my knowledge. If this is from my water having elevated levels of copper, what can I do to fix that? I have shrimp and snails and I know copper is toxic to inverts. However, is it possible it is just caused by me pouring water that contains fertilizers into my toilet?