Determining color change for TA

[waterbear]

The correct way to to this test (or any drop count test that involved a color change, such as calcium hardness) is to add drops until one last drop doesn't produce any further color change, then don't count the last drop. For example, say you put in 9 drop and got a red color, then a 10th drop and it got redder, then an 11th drop and the red stayed the same as the 0oth drop. You would not count the 11th drop and your test ended at 10 drops.

Aquarium, titration tests are very accurate, not appoximations! In the Taylor kit or Ben's kit the accuracy is 10 ppm for the TA test.