Where did all my CYA go


Active member
Jul 11, 2010
Ok, I've been doing BBB since about the second week in July.

Overall, I have been very pleased with the results, though I have cursed it a few times when I needed to add bleach at 8:00 PM and was completely out of it.

Anyway, I am using test strips to test my water, because budget did not allow for a good test kit this year. When I started BBB, my CYA levels were testing at 35. Since I thought CYA doesn't evaporate, I pretty much ignored the CYA on my strip and just checked free chlorine, ph and hardness.

Last night, I decided to check all 4 tests, and my strips say the CYA level is 0. How is that possible? It's mid-August now, and the pool will be closed the weekend after Labor Day, so I really don't feel like buying CYA this late into the swimming season.

I know I should probably buy a good test kit, or take the water into a store to have it tested.

But I am curious. How can one lose CYA?



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In The Industry
Apr 1, 2007
Sebring, Florida
I know I should probably buy a good test kit, or take the water into a store to have it tested.
That may bethe answer. Strips seem especially notorious for willd results when testing CYA.

If you put it in there and calculated the dosage carefully, then you probably still have some. YOu will lose some to splashout over an active period but not enough to bring it to zero. You could likewise have an auto-fill device and a leak in your pool but my prime suspect would be the strips.


Well-known member
Jun 12, 2010
NE Ohio
I've had test strips that were completely unreactive and some that reacted partially. If you are going to use strips I'd suggest that you take more than one reading because they can be all over the place. You can't beat a decent test kit!

That being said, why not get to your friendly local pool store?


In The Industry
Jul 25, 2009
London and France
I tested three pools at the start of the season, CYA levels 140, 160 and 190, the test strips from three different well known companies read 30-40 and 0

Make your own conclusions but the money wasted on strips vs the excellent Duraleigh TFP kit at an excellent price?
I cannot yet buy the component parts of that kit for anywhere near the money, trust me I have tried.


Well-known member
Aug 1, 2010
I've put 2kg's of Trichlor in my pool which should have raised CYA to 40 but my aquacheck strips still show 0, and they are 1 month old and were stored in the cool. :roll:

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