Copper went from 0 to 0.4 ppm in 2 weeks???

FernTheBrute

Well-known member
May 22, 2024
47
Québec
Never had a prior issue with copper and various pool store tests, from various stores, showed results of 0 all summer long. Last test was 12 days ago.

In the meantime, I switched to liquid chlorine and had some issues maintaining a proper Ph because my TA was around 100,which worked well with the stabilized tablets I was using previously. So I had to use a lot of Ph- (granular). Also used some algaecide, which I know contains copper,but I used at most 100ml in a 20 000l pool. Won't do it again. Also used some "non-chlorinated shock" after very heavy rains. I had used it previously without seeing raising copper levels.

Then today, booom 0.4 ppm of copper. I drained half of my pool not very long ago and I'm not particularly thrilled with the idea of doing it again to get rid of the copper.

I'm trying to figure out how could this have happened?
- The heavy rain (+100mm in 2 days)?
- The tiny amount of algaecide?
- The one-time chlorine-free shock?
- The 2 kg of ph- over 12 days? Can Ph contain Cooper? It's sodium bisulfate from the hardware store.
- Bad liquid chlorine containing copper? According to the product data it has 12% sodium hypoclorite and 1% sodium hydroxide

The only two new variables are the liquid chlorine and the heavy dose of ph-.

I don't have copper piping and my heater heat exchanger is titanium.

I'm not excluding a contaminated water sample or bad test, I'll have it retested somewhere else tomorrow. But I'm a bit lost. I know that from now on I'll stop using shock and algaecide,but I'm not positive they are the issue.

Also, besides draining, is there any way to remove the copper? And is 0.4 ppm safe?

Thanks!
 
Last edited:
Never had a prior issue with copper and various pool store tests, from various stores, showed results of 0 all summer long. Last test was 12 days ago.

In the meantime, I switched to liquid chlorine and had some issues maintaining a proper Ph because my TA was around 100,which worked well with the stabilized tablets I was using previously. So I had to use a lot of Ph- (granular). Also used some algaecide, which I know contains copper,but I used at most 100ml in a 20 000l pool. Won't do it again. Also used some "non-chlorinated shock" after very heavy rains. I had used it previously without seeing raising copper levels.

Then today, booom 0.4 ppm of copper. I drained half of my pool not very long ago and I'm not particularly thrilled with the idea of doing it again to get rid of the copper.

I'm trying to figure out how could this have happened?
- The heavy rain (+100mm in 2 days)?
- The tiny amount of algaecide?
- The one-time chlorine-free shock?
- The 2 kg of ph- over 12 days? Can Ph contain Cooper? It's sodium bisulfate from the hardware store.
- Bad liquid chlorine containing copper? According to the product data it has 12% sodium hypoclorite and 1% sodium hydroxide

The only two new variables are the liquid chlorine and the heavy dose of ph-.

I don't have copper piping and my heater heat exchanger is titanium.

I'm not excluding a contaminated water sample or bad test, I'll have it retested somewhere else tomorrow. But I'm a bit lost. I know that from now on I'll stop using shock and algaecide,but I'm not positive they are the issue.

Also, besides draining, is there any way to remove the copper? And is 0.4 ppm safe?

Thanks!
Pool store tests are really not reliable. The error tolerance for the copper/iron tests is pretty bad at that low level. Someone has a chart showing they can read 0.3ppm even when there is no copper in the water.

I had a similar issue on a brand new fill. The “for fun” pool store test showed 0.3ppm copper. The solution was testing at another pool store and it only read 0.1ppm.
 
+1. Their stated test varience is +/- 0.3 at 0.3. So 0 to 0.6 is questionable. A 0.2 (ok) might read a 0.5 (likely will stain) and vice versa.

At 0.6+ you probably won't need a test to know you have staining.

We used to send people to the pool store for metals testing figuring it was better than nothing, but once they published their tolerances, it's worse than nothing. It'll have people draining their pools for no reason.
 
+1. Their stated test varience is +/- 0.3 at 0.3. So 0 to 0.6 is questionable. A 0.2 (ok) might read a 0.5 (likely will stain) and vice versa.

At 0.6+ you probably won't need a test to know you have staining.

We used to send people to the pool store for metals testing figuring it was better than nothing, but once they published their tolerances, it's worse than nothing. It'll have people draining their pools for no reason.
Good to know. Is there any reliable home test that doesn't cost too much? And as for stain, do they come out with some brushing?
 
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