Forgive Me Pool Elders, I have Sinned (stain ID and removal help)

[Big Nodge]

Quick follow-up, I have not got around to doing the acid test as the stains have faded fairly dramatically just by keeping the pool at standard TFP FC levels. Does that imply it was more likely something organic, like leaf tannin? Either way, I’m not complaining. Although I still think I can improve my opening process to minimize this.

 

[Bperry]

Quick follow-up, I have not got around to doing the acid test as the stains have faded fairly dramatically just by keeping the pool at standard TFP FC levels. Does that imply it was more likely something organic, like leaf tannin? Either way, I’m not complaining. Although I still think I can improve my opening process to minimize this.

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Did you have a cover on the pool over the winter? That’s a lot of leaf outlines

 

[JamesW]

Try some sulfamic acid on a spot.

 

[YippeeSkippy]

Avoid an acid wash if you can as that will remove plaster and shorten the life of your pool.

Leaf tannin would be brown looking.... your pool floor looks like I'm seeing a film negative. Its the opposite of what I'm expecting to see? Odd.

A good cover next fall is in order, right?

 

[Wntrequinx]

Avoid an acid wash if you can as that will remove plaster and shorten the life of your pool.

Leaf tannin would be brown looking.... your pool floor looks like I'm seeing a film negative. Its the opposite of what I'm expecting to see? Odd.

A good cover next fall is in order, right?

Looks like whatever is causing the stains settled on the bottom, including on the leaves, so removing the leaves removed the presumably copper and left negatives where they had been.

That color looks like copper to me (not as bad as mine was, but there). If the water is getting more of a pretty turquoise as the stains fade, I wonder if that's the copper getting dissolved.

I had to partially drain and refill my AGP pool because of copper last year, and it had the lovely aqua tone yours does after I lowered the copper by 3/4ths. I took my water to a local store (that sold me the copper algecide) and also to Leslie's, and they had very different readings for copper, even at the same store at different visits.

My parents are in NH and actually use that same store (I haven't been able to convert my mother to TFP, sadly, but I keep trying) and I really think they use a machine there but if I'm wrong and they do manual tests, it might be 0 if they didn't do the copper testing (I had to specifically ask the non-chain store to do the copper test each time, since it's a relatively expensive test, they didn't do it for every person every visit, and the computer just printed 0 for any test they didn't do).

Edit- added pick of my high-copper pool after I lowered it to mediocre copper levels (from very bad). The bottom of that liner is all white, for reference.

 

[Big Nodge]

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!

 

[Bperry]

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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That’s a nice cover, how did the leaves get past it? I have a similar one but only a handful of leaves to get through it.

 

[Big Nodge]

There is a small hole and also some gaps near the diving rock, not sure if that is the full story. But the truth is I will need to investigate that this fall. There are tons of leaves in the pool area in fall, and I can keep closer tabs on when the lawn guys do the fall cleanup out there, maybe some end up blown under the cover. The pool crew that has opened and closed the pool for years (this is my second season owning this pool) indicated that given the trees in the area, leaves will always get under the cover and that’s just the way it is. But I know that’s not the final word, so I’ll add it to the list for further study this fall.