Thanks for the thoughts everyone. We do indeed use a cover in winter, it’s a large, irregular shaped pool with a custom cover. But there are a lot of trees around the pool. We have closed the pool in mid September in NH the last two years, and inevitably a lot of leaves make their way under the cover. I am not sure if it will be possible to prevent that in the future. If copper stains are the cause, what I can do is prevent any more copper from getting in the water. And if necessary I can def partially drain/refill.
Yeah, it was definitely a teenage girl at the store doing the test very quickly, so I don’t put a ton of weight on that. I think I posted it earlier but I do my own testing with a Taylor kit and only brought the sample to the store to see what the metal tests would say. Since it’s free I may try it again at some point, it’s an interesting theory that the stains fading may be a sign the copper is dissolving back into the water. But is it normal for copper stains to dissolve over time with a well-balanced pool?
Pic of the cover. Being familiar with my setup, it’s kind of funny that some are assuming I don’t use a cover. That isn’t exactly a cheap cover! If I didn’t the amount of leaves in the pool would be mind-boggling. But at least this year maybe the leaf barrier would have protected my floor!
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