CYA Accuracy

[Poolboy6]

Using a TF-100 my CYA reads zero. (I can see the black dot when filled completely.)
But I know it is not zero. I had the local pool company test it twice 2 weeks apart and they have a reading of 30 ppm both times.
Also my SLAM calculations are jiving at 12 ppm shock level when I add/test; so I am inclined to think pool store is correct.

I am certain I am following the instructions correctly.
Could the R-0013 Reagent go bad?
Does anyone have experience with inaccurate CYA testing using the TF-100?


FC: 5
CC: 1
PH: 7.0
TA: 80
CH:100
CYA: ?

 

[JVTrain]

In general, pool store testing for CYA is some of the worst. How did they test? Using the Taylor turbidity test or a whiz bang computer system?

Your CYA is likely not zero but less than 20 if it's clear to the top of the viewing tube.

 

[Poolboy6]

They are using Taylor test products for sure. And your point is noted: But I am 5 days into the SLAM and while it is premature for an OCLT test, my overnight loss is sometimes around 1ppm; and sometimes during sunny days it is less than 2ppm; wouldn't a CYA of 20 be unstable and cause massive loss of FC...especially when at shock levels of 12-14?

 

[RobbieH]

Test to be observed on sunny day with back to the sun. I seriously doubt the pool store is going outside to test.

 

[duraleigh]

PM me with your name and # and I'll call and help get you fixed up.

Dave