Hi Marshall,
The TDS reads about one half the ionic silver content so you double the
reading. The PWT reads about one to one. Does that make sense?
Once the PWT meter is calibrated using the standard solution of 84 uS the
meter is reading directly in uS from 0-99.9. That would also be 0-99.9
ionic silver PPM.
We do not calibrate the meters. That's up to the customer to do using the
calibration solution.
I hope this helps you,
Best regards,
Trem
[email protected]
www.silvergen.com
----- Original Message -----
From: "Marshall Dudley" <[email protected]>
To: <[email protected]>
Sent: Wednesday, December 28, 2005 9:43 AM
Subject: CS>TDS measurements
I am a little confused on TDS measurements. Trem says that when using the
Hanna
TDS meter he supplied me for measuring EIS, that the ppm of the molecular
ionic
part and the reading on the meter are approximately 1:1. The meter says
that it
is reading uS, but that is a nonsense unit, it has to be uS/cm or uS/in or
something, not just uS. Ole Coyote says that the reading should be
multiplied by
2 to get the correct ppm, and Frank Key at
http://www.silver-colloids.com/Papers/CSProperties.PDF indicates that TDS
meters
are calibrated for calcium carbonate, that has a ratio of .5 ppm/uS, and
that
ionic silver has a ratio of about 1.1. Thus one should multiply the
reading on
the meter by about 2.1 to get an approximation of the molecular ionic
silver
content which argees with Ode..
Then http://educate-yourself.org/products/tdsmeterdescrip.shtml indicates
a 1:1
ratio again which agrees with Trem.
So I am confused if I should be multipling the reading by 2 or not. Trem,
do you
recalibrate the meter for EIS before shipping it out, or is it the
standard
factory calibration?
Can anyone enlighten me on this?
Thanks,
Marshall
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