Hi. I use the Taylor K2006 test kit to test my water and the one test that I never really know if I am doing right is the CYA test. My question is, do I stop dripping sample into the small tube as soon as the black dot begins to disappear or does it have to be completely not viewable before I stop with the solution? At around 75 I can almost see the dot completely gone but it is very faintly visible. Any advice is appreciated. Thank you