Trouble testing CYA


Jun 20, 2012
Wynantskill, NY
I am having a hard time testing my CYA level. It still appears as though it is at zero, although it is kind of subjective as to when the cloudy water obscures the black dot at the bottom of the small tube. I have been adding stablizer a little bit at a time, but want to be careful not to overshoot.

I have this test kit:

Any suggestions? Am I doing this wrong or is there a better way to test your CYA level?


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
That's the same test the TF100 uses, although I think the view tube is smaller.

Unfortunately, that's pretty much the standard for CYA tests. I find it useful to take a reading, pour it back, mix again, and take another reading. Usually at least 3 out of 5 match, and that's the number I use.