CYA Test

[kjsmom]

So --- Michael's calculator calls for 16 lb of cya to go from 10 (we had new water last Fall and only added some closing chems) to 85. I added 9 lbs in mid April. Then I added 4lb 6oz in the a.m. on 4/22 -- buy my husband backwashed in the p.m. so I assume that was washed out. Then I added the 5lb 10 oz on 5/1. Disregarding the 4lb 6 oz that was probably washed out, the remaining 14lb 10 oz should get me to 80 ppm, right???? I will take another sample there tomorrow and see if maybe they made a mistake. I think I will just trust that I know what has been added and see how well my cl holds. Thanks very much.
PAT

[CarlD]

Did you backwash your pool in the meantime? If you added the CYA and then backwashed in a day or two, you would have flushed all the CYA you put in back out.

Why do you want to raise your CYA from 30ppm? That's generally an ideal number. Now you have 35ppm, so why raise it more?

You could slowly raise it by using a floater with Tri-Chlor pucks--just watch your pH because it will drop.

Still our first recommended range for CYA is 30-50ppm. You are right there!

On to testing: I test my CYA levels myself. I do it the same way everytime, so deviations are from my own tests and changes are baselined from my own tests.

Establishing baselines and normal ranges for the test site is very common. Every lab that runs blood chemistry and hematology tests sends along its baseline and normal ranges. These can then be "normalized" in pharmaceutical clinical trials so they can be compared meaningfully to other labs' tests when the new drug is submitted to the FDA for approval.

[duraleigh]

Pat,

I think I will just trust that I know what has been added and see how well my cl holds.

That is a very wise decision. Pool stores notoriously don't test accurately. Get a kit that tests for CYA (Ben's is the best) and your pool chemistry management will become amazingly accurate.