I am having widely varying CYA readings from 45-70. I know it’s not that reliable, but what factors affect the readings? With levels making such a difference in disenfectant effectiveness, there must be a reliable test method.
For me anyway, I have found that doing my test outside with my back to the sun and NOT wearing sunglasses has yielded me the most consistent and accurate (I think ) results.
I will defer to other more knowledgeable and experienced members who might use a different if not better method for testing.
Good luck. You'll get it with practice.
No. The reagent is stable and if it works at all, it works.....no variables to speak of.
Perform the test as normal and note your result. Now, pour the sample into another vessel like a styrofoam cup. Then, pour it back into the view tube and read the test again. Last, do it one more time so you have had three opportunities to evaluate what you see. If they don't match up, take the average and that is your CYA.