Re: TDS3 meter arrived, findings from my experiment

To my understanding, you don't have the wrong meter.

A TDS meter reads ppm, but is calibrated for ppm of dissolved salts, whereas ionic silver is not a dissolved salt, so a correction factor of about 2.4X to 2.5X is required and appropriate.

The Hanna PWT reads in units called uS (Micro Siemens), and not in TDS (or ppm). It is only by luck that a meter designed to read disolved salts in units of Micro Siemens (uS) gives ionic silver readings that are pretty close to actual ppm.

For either type of meter only the ionic silver component is possible to read via the meter. If you assume that about 83% of what you have made is ionic and 17% is colloidal, then 100%/83% = ~1.2. To read ~ppM silver in units of uS (as would the Hanna PWT meter) you should therefore multiply the reading of the PWT by 1.2.

The 2.5X factor for the TDS/ppM type meter and silver has this 1.2X factor built into it.

The bottom line (per my understanding to date) is:
1) If your meter reads in TDS/ppM units multiply by 2.5
2) If your meter reads in uS units multiply by 1.2 Tweet