Cya going up??

[jcaj558]

I did a partial drain about a month ago. Got my cya down to about 85. I haven’t put anything in other than Liquid chlorine and some Lo and Slow ph reducer. I test the cya this morning and it read about a 100. Just took a sample to the pool store and they said it was 140. The use the Bioguard Alex system. Which one should I believe? With either number what could be making it go up? I use a Taylor k-2006 kit.

 

[DorsalSpine]

Unless you added something with CYA in it the level didn't change. I'd call it testing error and go from there. You can always dilute your water sample 50/50 with tap water and retest. Double the result and see if it is close to 100.

 

[jcaj558]

I did the dilution test and it was 50 so I doubled to 100.

 

[DorsalSpine]

Then I'd say it's probably 100. The difference between 85 and 100 is probably testing error.

 

[jcaj558]

When I did the drain about a month ago I tested it at 90. Being new to testing myself I brought a sample to the pool store to compare and they had it at 89. Now I’m getting 100 myself and the ps is getting 140.

 

[PoolNewb2020]

I would not go to the pool store. It will only make you doubt your own testing.
Did you follow the steps outlined here?CYA testing

If you still have trouble, you can order a sample for test kits that is 50ppm CYA and practice on it.

 

[jcaj558]

I do follow those steps.

 

[PoolNewb2020]

Did you have sun at your back during both tests?

I just happened to do my CYA test few days ago and initially I got 60ppm, whereas a month prior it was 50ppm. I realized that I was doing the test in shade. I moved to a sunny area and got 50ppm.

The amount of ambient light available really plays a big role in this test.

 

[BK MAC]

My pool store also uses the Alex system. As CYA is a rather subjective test with the test kit, I thought I'd take my sample to the pool store to compare test results. While our results have been in sync in the past, this time they said my CYA dropped from 70 to 30 in one month (no drain down or any other reason it would have gone down that much). Based on my testing I knew it was in the 60-70 range. They were completely off on my TA and pH levels as well. I don't know if it was the Alex system or employee error. I'm just glad I test my own water and "know" my pool better than they do. If I doubt the result, I'd rather retest my own work than assume the pool store results are accurate.

 

[Donldson]

I don't know if it was the Alex system or employee error.

Does it matter? The job of pool store testing is to draw in potential customers and put them in front of salespeople. Since that doesn't require accuracy calibration is not a high priority. And the salesperson's job is (brace yourself) to sell something. They aren't "water testing people", they are just doing that to get you to possibly buy something.

Pool store testing is unreliable and this thread proves is more likely to confuse than to actually help. There's no reason to do it.

 

[BK MAC]

Does it matter? The job of pool store testing is to draw in potential customers and put them in front of salespeople. Since that doesn't require accuracy calibration is not a high priority. And the salesperson's job is (brace yourself) to sell something. They aren't "water testing people", they are just doing that to get you to possibly buy something.

Pool store testing is unreliable and this thread proves is more likely to confuse than to actually help. There's no reason to do it.

 

[jcaj558]

Thank you everyone for the information. With all that said is there anything that would make cya go up other than using the wrong chemicals?

 

[mknauss]

The only way to raise CYA level in your pool is for you to add it. Common items are trichlor (pucks and powder), dichlor (powder), and stabilizer/conditioner (powder or liquid).