Re: TDS tester (for PPM)
It can be done with a conductivity type meter and a carefully controlled process. However, you'd still need to establish a baseline, which would in turn, require some careful monitoring and calibration. ie, You could combine a theoretical calculation with a physical weight differentiation to get to what I'd call a close to accurate rating. ie, using a analytic lab scale(.1mg resolution is best), you could weigh your anode before and after processing to compare against your theoretical calculation. Keeping in mind that the weight of the anode will be influenced by oxidation and other impurities and that this will only get you an approximation(+/- 1-3ppm). Though close enough to give you a good idea of what your total silver in solution is. ie, never being more than... the total sum etc.
That being said, I've discovered that it is not possible to process anything beyond 19ppm without
additives with the heat(98-100c) method and where the room temp solutions proved to have an even lower threshold(At or around 17ppm), before pooling and/or plating occurred.
Hope this helps.
PS. There is a
Colloidal Silver generator company that sells HANNA meters with calibration fluid. Though it looks like they only claim this to work with there own generators. And so, not sure how much help this would be for someone making there own.