Hi Bob, We tried the Hanna spectrophotometer and it never worked for us. We returned it. That's when we found the Hanna PWT meter worked quite well for the purpose and was very repeatable. Even though they only read the ionic portion and a correction factor is applied to get the total amount of silver, they do read accurately enough for any average persons needs.
We use three of them to average our results during calibration of the generators we sell and they all read the about the same every time. They give true readings after the correction factor is known. In our case, CS made with our generators has always been 85% ionic and 15% colloidal as measured with atomic absorption testing so we took the PWT readings and applied the correction factor. Of course someone using a different setup than ours would measure only the ionic portion correctly but the point is....it will be repeatable and since most LVDC is between 80 and 99% ionic, the readings would not be off more than 1 to 20%. My understanding is that most LVDC CS made with constant voltage and 14 GA. wire is typically 90% ionic so one would just multiply the reading on the PWT by 1.1 to get a fairly accurate measurement. This is the best and inexpensive method to test home made CS. It allows one to monitor their production and get repeatability with their process. After all that's what most people want...is to know what's going on in their vessel from batch to batch. It is especially useful if one is using the constant voltage process because CS production isn't a linear process compared to time as it is if one uses constant current control. Since our generators use constant current and are very repeatable and consistent over any increment of time, the use of these meters isn't really necessary. However we do sell a lot of them and they are good devices for the amount of money they cost. A couple of lab tests cost as much as the meter which will test thousands of batches on one set of batteries. Trem ----- Original Message ----- From: <bober...@postoffice.swbell.net> To: <silver-list@eskimo.com> Sent: Monday, December 24, 2001 7:02 AM Subject: Re: CS>Re: argyria > Hi Leo, > > The least expensive instrument that will actually measure ppm of silver is > sold by Hanna. It is a single frequency spectrophotometer and cost $150.00 > plus about $100.00 for the chemicals that are required. > > My spectrophotometer was a new military surplus for $250.00. > > All other low cost meters only measure conductivity which will give a relative > reading but not a true reading. > > "Ole Bob" > > > -- > The silver-list is a moderated forum for discussion of colloidal silver. > > To join or quit silver-list or silver-digest send an e-mail message to: > silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com > with the word subscribe or unsubscribe in the SUBJECT line. > > To post, address your message to: silver-list@eskimo.com > Silver-list archive: http://escribe.com/health/thesilverlist/index.html > List maintainer: Mike Devour <mdev...@eskimo.com> > > > >
