Question about CYA test using Taylor K-2006

Every time I've used the kit to test my CYA, I always wondered about this and decided to finally ask: The instructions say to add the mixture to the tube until the "black dot just disappears".

I'm getting a little older and my eyesight is not what it once was but if I squint and can still see the black dot, do I add more until I cannot see the black dot?

Moblaine,
I know what you mean by if you squint, you can still make out that dot. It's a judgement call and not a very precise test. When you get to that point, the difference between the readings would not be significant.