How often do you test CYA?

Bicster

Well-known member
Jul 4, 2018
78
Toronto, ON
The title says it all really. How often do you folks test your CYA levels?

My solar cover deteriorated and since then it’s been burning through FC. I was anticipating it using more than usual, but it’s going through a lot. I have no CC, ph is 7.5 and the water looks great, so I was scratching my head trying to figure out what was going on.

I then measured CYA and couldn’t get a reading - which is obviously my problem.

Yesterday I added enough CYA to get me to 45ppm (thank you pool math) and will test again tomorrow to see where we’re at. I also added a generous amount of chlorine under the presumption we’d be at 45 ppm of CYA pretty soon.

I don’t think I’ve tested the CYA since maybe early June. So, how often should I be testing?
 

Cwiggs

Well-known member
Aug 31, 2019
117
Phoenix, AZ
The tf-100 test kit says CYA is a weekly test, I tend to test once a month, but unless you know your pool better you might want to do more. I'd be interested in hearing what others say though.
 

Bicster

Well-known member
Jul 4, 2018
78
Toronto, ON
Oooof, need to up my game a little then I guess!

I was thinking once a month, that seems reasonable, maybe more if it’s being used frequently needing regular top ups.
 

jark87

Silver Supporter
Jun 5, 2011
202
Flower Mound, TX
Roughly once a month during the summer when I have lots of evaporation. Hardly check it at all during the winter, which is probably not the recommended practice.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,053
Central California
Depending on how you add the CYA, it can take longer than 24 hours for an accurate test result. If you get 45 right away, then you're good. But if not, I'd wait another day or two before I added more CYA. You can overshoot if you don't give the CYA enough time to mix in, especially if you get some trapped in your cartridge filter. I test a few times a year. Once a month seems prudent until you know your pool better. CYA does break down over time, and can be lost if you have a lot of splash out going on, or vacuum to waste a lot, but it doesn't evaporate or get used up at anywhere near the same rate as chlorine or acid.

Oops, by the way, TFP rounds up CYA test results to the next "10," so its 50, not 45.

Here's more about CYA testing:

 
Last edited:

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
18,727
Bedford, TX
B,

I only check mine at the beginning of the our pool season and if it appears I am using too much FC... For me anyway, the first indication that my CYA is low, is that my FC demand goes up.

Thanks,

Jim R.
 
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markayash

Gold Supporter
Mar 21, 2016
2,373
Marietta Ga

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,053
Central California
I found a huge bottle of the stuff on Amazon, for cheap. I may not use it all before it expires, but it was that cheap!

Just checked, still there. 16oz for less than 20 bucks. For that you can test 'till your heart's content!

It's the same price as three of the 3/4oz bottles...