Please clarify your dose/day and how you do this. I know the amount added is extremely tiny and when I read this I became curious about the process.I dose copper daily into my display. Since I run ozone, it gets depleted quickly (as seen by my ICP-MS results). It is an essential compound for photosynthesis, so I add a very small amount to keep it just barely detectible on an ICP-MS test (it should never be detected on an ICP-OES test).
Also, someone trying to save a fish using copper might think your method could work for that, and nothing could be further from the truth in application than what you are doing and trying to cure a sick fish need to do, imo.
I didn't know running UV had these kinds of impacts upon the water contents. I guess I still have lots to learn. Thanks!