Total Alkalinity test ambiguity

[MPurcell]

The Taylor instructions for the TA test say:

"Add R-0009 dropwise. After each drop count and swirl until color turns from green to red."

The TFP Extended Test Kit Directions for TA say:

1. Continue adding drops until the color changes to something more or less red, pink, yellow, or clear. The sample may switch between green, blue, and gray while you are adding drops. That is not the color change you are waiting for.
2. Continue adding drops as long as the color continues changing. The final drop, that does not change the color any further, does not count.

So, in my example, drop 5 turns the color from green to dark grey (really between green and red), drop 6 turns the color slightly more red than green, and each subsequent drop makes the red color become more bright and rich until drop 12 makes so little difference you can't really tell if the red is deeper or not. If I were following the Taylor instructions, I would stop at drop 7 and call TA 70, since the color is clearly red. However, by the extended instructions, the TA should be 110, so I'm assuming that the TA is really 110. Does this agree with other people's experience?

Thanks,
Michael

 

[Richard320]

Yes.

I use a speedstir and a lot of times that grey color will revert back to green with a few seconds more spinning. And I also get multiple shades of pink. If there's still some color changes to be made, there's still some TA that hasn't been counted.

 

[pooldv]

Yes, step 2, Continue adding drops as long as the color continues changing. The final drop, that does not change the color any further, does not count, is the key to testing. And get a good swirly going in the tube.