Titration accuracy/resolution question

Northern Brewer General
1

I’ve just starting using the LaMotte BrewLab and am wondering about how to interpret titration test results. In essence if “1 drop =10 ppm” and “2 drops = 20 ppm”, and 1 drop results in no change in color but the 2nd drop results in a full change in color, what is the concentration?

My guess is that it could be anywhere from 11-20 ppm.

I prepared rough graphs to illustrate (I don’t know how closely they would resemble a real titration curve).

For high concentrations a difference of 10 ppm wouldn’t matter much…it is the lower concentrations I am concerned with, since for small concentrations, things like sulfate/chloride ratios can vary widely.

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2

I believe in a titration test the color change is an end point calculation so 2 drops = 20ppm. You say 10ppm wouldn’t matter so 20ppm is fine. If you need to be more accurate you have to increase your solution. W
hat are you measuring?

3

The test kit has titrations for total hardness, calcium hardness, total alkalinity, and chloride concentration. Magnesium and sodium are based on those tests, and sulfates ae measured via turbidity.