Ode Coyote <[email protected]> wrote: [...]
>No meter will measure "PPM", but the numbers are about the same between a >devise that will measure PPM and conductivity readings from a meter that >won't at around 10-12 uS =10-12 PPM.....after the conductivity stops dropping. > >The relationship slews off each way in both directions from there a little >bit for a good guess and beyond 30 uS, all bets run off into make a wild guess. > >Ode If you are seeing a significnt conductivity drop after the brew is finished, you have a contamination problem, most likely silver sulfide, or severe leaching from your soda-lime glass. This can easily give 60% drop in conductivity. If you remove the contamination, the conductivity drop should be around 8% or less. The conductivity of a solution is defined as the reciprocal of the resistance of a 1cm cube. The conductivity is directly proportional to the number of charge carriers in the solution. This is a linear function over the entire range of conductivities we use. For example, the Hanna HI 7033 Calibration Solution is 84uS/cm at 25C. This is a single point calibration, meaning all other measurements fit on a straight line down to zero and are a linear function of the conductivity. For silver and hydroxide ions, the relationship between conductivity and ppm is 1uS = 1 ppm, providing you have no contamination. I did a study long ago that shows this. Note the measurements cover the range of 3.3uS to 26uS. Here is the url: http://silvercentral.org/measure/1us2ppm.htm There is no reason to expect any deviation above this value, for example in the SilverCell process that can easily reach 44uS. If your measurements indicate the results above 30uS are a "wild guess", then there is something seriously wrong with your measurements, or you have significant contamination problems, or both. Since you seem to be insensitive to contamination problems, I would guess both. Thanks, Mike Monett -- The Silver List is a moderated forum for discussing Colloidal Silver. Rules and Instructions: http://www.silverlist.org Unsubscribe: <mailto:[email protected]?subject=unsubscribe> Archives: http://www.mail-archive.com/[email protected]/maillist.html Off-Topic discussions: <mailto:[email protected]> List Owner: Mike Devour <mailto:[email protected]>
