TDS: 129ppm - Total Alkalinity: 160ppm ??? Error?

[cannman]

I was wondering if it was normal for a TDS meter to report lower values than the total Alkalinity (or bicarbonate for that matter) from the same sample?

TDS: 129ppm - Total Alkalinity: 160ppm ??? Error?

I'm getting a grasp of this water business so thank you for your patients.

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here's the results:

Sample 8/3/2016

Tds – 129
Chloride – 30 PPM
Sulfate – 0
Total Alkalinity CaCO3 – 160 CaCO3 PPM
Bicarbonate (HCO3) – 192 ppm
Total Hardness CaCO3 PPM – 100 ppm
Calcium hardness – caco3 – 60 ppm
Calcium Ca+2 - 24
Magnesium Hardness (CaCO3 ppm) 40 ppm
Magnesium Mg+2 - 9.6 ppm
Residual Alkalinity – 22.857 ppm CaCO3
Sodium – 57.1711 ppm
Negative Ions .0857 + 3.2 = 3.2857
Positive Ions 0.8

 

[ajdelange]

Given the other data your TDS is actually around 315 mg/L.That is the total weight of the ions you listed. This has but loose relationship to the TDS that is measured with a TDS meter which actually measures the electrical conductivity of the sample and computes the weight of (usually) NaCl which would give that conductivity in DI water.