cya 0 after nearly 3 1/2 lbs. stabilizer

[fullhouse]

sorry should have posted volume. i have an ag 10,500 gallon vinyl liner.

[Watermom]

I would think you should be getting a cya reading. I'll have to go and look at my container to see what 3.5 lbs should've added to that volume. I can't remember off-hand. Somebody else may have that info in front of them and can reply. At any rate, I'd give it a few more days, just to be sure and then I'd go slow with adding a little more. Better to gradually get it where you want it than to overshoot and have the level be too high.

[Sherra]

According to the BleachCalc it should be 40-45 PPM.

[DavidD]

I'm in agreement with Sherra. I don't have any ideas what could be causing this but have had a similar experience with pool stores testing for CYA. I was in the “good” Pool Shop in town early this year getting poly etc. and had them test my water, even though I'd just tested with the Ps233. Everything was very close except the CYA. They came up with 15 ppm, I came up with 30 two times in a row. Went to a "bad" pool store that is right up the road and the professional there (17 to 18 years old and a pound of chewing gum in her mouth) came up with 10 ppm two times in a row. Now I'm perplexed. Is Ben’s kit wrong? Have I been off all these years? I then pulled out an old Pentair kit I got with the pool. It has the tablets for testing CYA. The package was in good shape so I gave it a whirl, twice. Both times tested 30+/-.
Moral of the story: Do your own test.............