Thanks for your kind words George. Yes I did state that 0.57uS equalled 1ppm as silver (at 10ppm), but noted that this was a theoretical number. This multiplier holds true when one measures silver nitrate for example. However the measurement of colloidal silver in actual practice reveals a multiplier of about 1 to 1.2. I do not know why this should be so (perhaps we are measuring clusters of ions) nor why there should be a range of multipliers, other than stating the obvious that different processes produce different CS characteristics.
In my own case the multiplier is about 1.0 (which is quite convenient), I produce >90% ionic CS. The only way to achieve accurate results, is to calibrate by testing for silver by another method and then if you keep your process the same your conductivity conversion factor should be pretty accurate. I am fortunate to posses a Silver Ion Selective Electrode which enables me to accurately measure the concentration of silver ions, with out the worry of interfering species, Cheers Ivan -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Friday, 29 November 2002 9:36 a.m. To: [email protected] Subject: CS>PWT -- TDS COMPARISON Ivan, In the comparison of PWT -- TDS readings I posted on 11/18, the TDS readings are what the meter measured . What I multiplied by .57 was the raw reading of the PWT. Thus: PWT TDS 30 x .57 = 17.10 16 19.49 x .57 == 11.11 10 27.49 x .57 = 15.67 14 For the PWT results: where the third decimal place was more than 5, I rounded up. In response to my posting, someone responded that you had changed the multiplier from .57 to 1.2 Is this correct? I believe there are a good number of non-technical types like me on the list who would find an explanation by you of how to achieve accurate PWT readings as useful as are most of your other posts. George
