TDS factors for concentrates

Hello,

I just finished the water course on BH and I started to prepare myself some concentrates (1L bottles 1000 ppm).

Where do you guys keep the bottles with the concentrates?

In the fridge or can they also stay inside a closet? The plan is to open them every week when I buy a 5L bottle of distilled water and make my water for filter extractions.

How stable would the concentrates be? I have an Apera TDS20 meter and I plan to take some measurements but since I don’t really trust the temperature compensation of the device it’s a bit hard to be consistent (pretty hot these days in Vienna).

I’d like to validate that the concentrates really have 1000 ppm.

To which is TDS factor should I set the meter to? Currently I have it on 0.71 which is OK as this relates to the 442 standard which is used by SCA.

I made two calculations but I am unsure of them:

  1. The concentration of 1.68g of NaHCO3 in 1L of pure water should be 19.99 mmol/l so if I enter this here aqion - Online pH Calculator it shows me a conductivity of 1726.9 µS/cm so the factor should be 1000/1726.9 = 0.579

  2. The concentration of 2.45 of MgSO4·7H2O in 1L of pure water should be 9.94 mmol/l so if I enter this here aqion - Online pH Calculator it shows me a conductivity of 1392.7 µS/cm so the factor should be 1000/1392.7 = 0.718

Is this accurate?

Cheers!
Andrei