CYA Testing

[Sumo1]

I have a Taylor K-2006 test kit with the CYA test that instructs to stop adding reagent when the black dot disappears. For me that seems to be a very inexact measurement and I can get varying test results from one test to the next. I'm not sure the time to stop is when the dot first seems to be gone or keep adding reagent until the dot's absolutely obliterated!:confused: Does anyone else find this test confusing or have any tips or ideas that might help? TIA
Hal

[duraleigh]

The test is imprecise by it's nature. You should add solution until the black dot disappears completely.

To get repeatable results, it is helpful to always perform the test in the same lighting conditions. This usually means indoors in the same spot. Results will still vary a little but it should get you close enough for the test to be meaningful.

[Poconos]

I use fluorescent desk lamp light reflected off a white card and look down through the tube with the light coming up from the bottom. The results closely match the recommended method of using direct sun and viewing at waist level. I think that's the recommended way. And yes, the measurement is a judgement call and I let the dot completely disappear.
Al

[chem geek]

For what it's worth, this link (http://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=44) at the Taylor website has pictures of the CYA test (scroll down) that give an idea of how the black dot disappears.

[giroup01]

Or this blast from the past!

[Sumo1]

Thank you for your responses!:)
Hal