CYA Measurements below Room Temperature

[macmini]

Hi. Quick question:

The extended instructions for the CYA test in TF-100 test kit tell me to "allow the water sample to warm up to room temperature (70) before continuing". I did the test for a friend with water that was at 61 degrees. Is there a difference in the end result that is large enough that I should retest?

Thanks.

 

[chem geek]

It's probably OK, but if you didn't wait long enough that it might read lower than the true value. The reaction is slower at colder temperatures. On the other hand, if you wait longer at the colder temperature, the reading can be artificially high since the precipitate is less soluble (though in the Taylor test they try and minimize that effect by lowering the pH). See this post that indicates that at 60ºF your reading is probably OK. It's at 40ºF that if waiting long enough it reads artificially too high for the CYA test.