Hi James,
Hanna is incorrect. They will be the first to tell you they don't have any
idea about using the PWT to measure CS. Fact is, with our generators which
always produce 85% ionic, we add 20% to the reading after subtracting the
initial DW water reading to get the total CS reading....ionic and colloidal.
It always agrees with our AA tests within a small percentage. Plenty close
enough for government work.
The TDS is useless for measuring CS. It is accurate to + or - 2% of full scale
which is 20 parts. How do you expect to measure in the 5-15 PPM range with a
meter that can be off by 20 digits? Use it on something that will get the
reading up in the midrange readings such as tap water, etc.
You're right. The TDS reads about half as much as is really there.
Trem
----- Original Message -----
From: James Allison
To: silver-list@eskimo.com
Sent: Monday, December 24, 2001 12:32 PM
Subject: Re: CS>Measuring CS strength
Hi Trem! Hanna told me to take the PWT reading and divide it in half for a
"fairly" accurate reading of PPM. When doing so, at least for me, this almost
always equals the reading of the TDS1 meter. I'm talking LVDC CS, and I have
no idea how it would equate out to non-ionic. I personally like the TDS1 as
there's no conversion factor, and it reads up to 999 PPM, and it's also good
for testing when I need to change my filters on my water purification unit ;)
Please let me know if you've got different info than I do, thanks!
-James
----- Original Message -----
From: Trem
To: silver-list@eskimo.com
Sent: Monday, December 24, 2001 12:09 PM
Subject: Re: CS>Measuring CS strength
Hi Bob,
No I didn't because the unit came with the reagents supplied by Hanna. No
reason to try and second guess the manufacturer, eh? We followed their
directions to the letter and it never gave reliable readings. Nor was it
repeatable. It is made for measuring silver in effluent, etc.
The PWT is still the best choice for most people.
Trem
----- Original Message -----
From: <bober...@postoffice.swbell.net>
To: <silver-list@eskimo.com>
Sent: Monday, December 24, 2001 10:02 AM
Subject: Re: CS>Measuring CS strength
> Hi Trem,
>
> Did you buy an NBS certified standard of AgNO3 to calibrate your meter?
If you
> did not then it will never read correctly.
>
> It took several days to calibrate my spect. as it is a lenghtly process.
>
> "Ole Bob"
>
>
>
>
> --
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