Hi Pavel, It turns out the PWT does double purpose. It measures uS of the water and in my opinion measurements to a tenth of a microsiemen are plenty good. After all, this isn't rocket science.
It then measures the ionic portion of the mix after the silver is put into the water. It does not measure the metallic (colloidal) portion. We then use a correction factor to estimate the total amount of silver. This is the best low cost instrument for our purpose. And yes, it will probably read differently in different solutions but that will not make any difference if you know the correction factor to use. We know the typical correction factor for silver is to add 10-20% to the reading. You would have to send samples of whatever else you wanted to establish a correction factor for to a laboratory for analysis. You would then have the ability to determine that particular correction factor. We did it for silver at 2 different labs using atomic absorption spectophotometry and accept the results. Best regards, Trem ----- Original Message ----- From: "Pavel Hochmut" <[email protected]> To: <[email protected]> Sent: Wednesday, April 21, 2004 2:30 AM Subject: [silver_list] CS>The Hanna PWT meter, conductivity vs. ppm values > Hi, > I have looked for what the "PWT" means on the Hanna www.pages. > Both devices mentioned below are from Hanna and are designated for measuring > the conductivity. Both of them can ONLY measure the conductivity as every > other ordinary conductometer does. There is nothing more. > The "PWT" only means "Purity Water Tester" and determinates the device rank > of accuracy in the spread of Hanna products. Nothing more. > Now I understand the words "I have never seen the PWT meter showing more > than one decimal place" (from Trem)... it´s correct, because it is it´s main > feature - the range of the Hannah HI98308 "PWT" meter is 99,9 - 0,1 > micsoSiemens with the 0,1 microSiemens resolution. > If you look on the Hanna pages more carefuly, you can also find the HI98309 > "UPW" meter (the UPW means Ultra Pure Water tester) with the range 1,000 - > 0,020 microSiemens with the resolution of 0,001 microsiemens. > So: who has the HI 98309 UPW model, he can measure the conductivity more > precisely having dvo decimal places more than with the PWT model. But the > UPW model is approx. 3 times more expensive than the PWT one. > So, one who says: " I have measured my DW and it has 2,9 PWT tells it wrong. > Correctly should be said: 2,9 microSiemens (...measured with Hanna PWT > meter). > You can also see simple conductivity/resistance conversion charts on the > Hanna site as I already wrote about. > This reminds me that I saw posted some relation between the conductance and > ppm values. That seem to me incredible, because the substance (dissolved or > in the colloidal estate) may have different influence to conductance of the > (say) batch. For instance let´s put into the > 1 cubic cm (1 ccm) of DW 2,000.000 atoms of silver. > And put to another 1 cubic cm of DW 2.000.000 atoms of Si (silicium). I bet > my year´s income, that the resulting conductance measurements shall be > absolutely different. I swear. > Or can somebody mend my opinion? Where´s the mistake? > Thanks Pavel H. > > > > > > > -- > The Silver List is a moderated forum for discussing Colloidal Silver. > > Instructions for unsubscribing are posted at: http://silverlist.org > > To post, address your message to: [email protected] > Silver List archive: http://escribe.com/health/thesilverlist/index.html > > Address Off-Topic messages to: [email protected] > OT Archive: http://escribe.com/health/silverofftopiclist/index.html > > List maintainer: Mike Devour <[email protected]> > >
