CYA test is pretty subjective, isn't it?

[PatL34]

This test is very subjective. So much so that I have had to remove the subjectivity as much as possible.

My method is painstaking, literally, but is as follows:

1. Clean the tube that has the spot with bleach before EVERY test.

2. Follow the instructions for adding the sample and CYA. Wait at least a minute before the next part. Shake the mixture thoroughly to get the best reading.

3. Go to a north facing window. Check the point at which the black dot appears or disappears, depending on the equipment and test procedure. Make sure that your fingers are not covering any part of the tube.

4. As soon as the dot appears or disappears, that is your reading. Do not try and find another reading if you don't trust your eyesight. If you don't trust your eyesight, find someone who can. I am not being sarcastic here, just trying to make sure the test is being done correctly.

This test is difficult enough without being consistent, but as Ben says it is the most subjective test you will do in checking for CYA.

Hope this helps.

Pat