Testing copper levels

[jwlv]

Back before I found TFP, I’d take samples to Leslie’s for testing. I’ve since bought my own test kit and have been testing myself. When I was taking water samples to Leslie’s, they’d always be positive for copper. The results varied, anywhere from 0.2 to 1.1 ppm. At one point I drained the pool for an acid wash and after refilling it found no changes in the copper results from Leslie’s. I know, I know, this is shocking!

I bought the Taylor K-1738 copper test kit which returned a completely negative result. My test sample was 42F so being unsure if this test was temperature sensitive like CYA, I warmed another sample by placing the test vial in another container of hot water being sure not to contaminate my sample. After five minutes I got the test sample up to 73F and repeated the test. It turned out again to be negative. Does anyone know if this test is indeed temperature sensitive, and if it is, was my method of warming the sample appropriate? Anything else I may possibly be doing wrong in the test process or is Leslie’s copper test really that bad?

Also, the Taylor K-1738 test kit came with caps for both regents along with two seperate pipets (see example picture below). Is it safe to replace the cap with the pipet for storage of the regent or does storing the regent with the pipet result in a less effective seal?

 

[Texas Splash]

I'll sure @JoyfulNoise can answer the question about the test itself.

I'm curious, is there a pool product you have used in the past that had copper in it? Any mineral sanitation devices? If not, copper would seem unlikely.

 

[Texas Splash]

I see now you have three copper scuppers so........ Hmmm. Have you ever seen your pH drop too low previously? That's the only thing I can see that would've possibly added copper.

 

[JoyfulNoise]

Cold temperatures will slow the test down but it shouldn’t affect the results. If you warmed the sample up to room temp, then the test is valid. A small temperature change like that would have no effect on the copper that may or may not be in solution.

Store the reagents with the original caps on, not the eye dropper caps. Since you are testing infrequently, you don’t want the reagents to be exposed to air. Reagent #1 has ammonium hydroxide in it which makes it air sensitive and the Reagent #2 has isopropyl alcohol in it which can evaporate if not tightly sealed. You’ll want to keep those test reagents stored in a cool and dry space to maintain shelf life.

 

[jwlv]

Have you ever seen your pH drop too low previously? That's the only thing I can see that would've possibly added copper.

Yeah, the pool service company I previously had let the chlorine get too high (15-20 ppm over 2 months) which I believe skewed their pH and alkalinity results. Once they neutralized the chlorine, the pH and alkalinity results were at the bottom of their scales. That being said, the Taylor copper test is returning 0 ppm of copper so that's good.

 

[JamesW]

is Leslie’s copper test really that bad?

They just increased the total training time for new employees from 10 minutes to 15 minutes, so I suspect that the testing procedures will be better in the future.