4/04

PPM meters measure conductivity and converts these figures into a PPM reading for total dissolved solids. Calibration and possible unique characteristics of CS may be a problem for meters that are not specifically designed to measure CS. [none are]

Resolution of PPM meters is pretty dismal and the possible error is quite high at the low end of its range.

ALL meters measure only ionic silver content in solution. Tyndal effect [laser light reflecting off colloid sized silver particles in suspension] is an indication of colloid particle content but Tyndal doesn't give a "calibrated PPM reading". The two together are the "total silver" content, both in solution and in suspension in variable ratios.

Further, some "ionic" silver agglomerates into "colloidal" silver with time so PPM meter readings tend to drop as a Tyndal effect begins to develop. The silver didn't go anywhere.

If you are using a meter that reads in PPM, double the reading to get an approximate value in microsiemens. Series 2 generators produce an approximate PPM equivalent to the microsiemens reading "after" conductivity has stabilized.

..and there's another possible problem. If the water has some contaminants, meters can't tell the difference between those and silver, nor can the generators circuits. So, if you use contaminated water, the 'run time' is short and you send off samples to be assayed specifically for silver...and nothing else, the PPM [of silver] can turn up much lower than the conductivity readings would indicate.

There is some disagreement on how readings from the various meters are to be interpreted. There is some varience from person to person and meter to meter and cross calibration is, well...up for grabs?

My DIST1 PPM meter hits the trash can where it belongs!

Date: Mon, 01 Dec 2003 12:09:55 -0500
X-Loop: silver-list@eskimo.com
Subject: CS>Test Results from Colloidal Science Laboratories, Frank Key

OK Folks
Here it is from Frank Key, in bold [ouch] print as promised in the light of operating truthfully "to the best of my knowlege"
[That's the "kicker"]
These results were obtained using the lastest version of the series 2 silverpuppy generator [gts2b1] to run batches.
I have no idea how they apply to previous versions except that they are set to shut down at nearly the same conductivity and voltage references within .06 volts and 100 ohms.as 'seen' at the electrodes.

My reply to Frank Key:

Your uS readings are very close to my re-calibrated PWT [ie, PWT is working properly..at last.]

Here's what I recorded. [An Experiment that was run to show heat effects on PWT readings showed about +1 uS change per +10 deg F. as 'worst case average']

Batch #1 22uS at finish @ 91.1 deg F
11.1 uS in 8 days
Very faint TE with little change during stabilization period. This was an unexpected occurance seeing the amount of conductivity drop...possibly....mostly very very small particles not into red laser range of visibility? [Deemed probable and provable] Maybe, Super-conductive unstable ions???? [well....]

What I "figured" using Trems uS x 1.2 fudge factor...[silver making process is virtually identical except for temperature. Fudge factor derived from his results from same lab.]
It's established that virtually all content is ionic at first, later, forming most of the non conductive particles which accounts for conductivity drop over time.
So, I used the initial conductivity at finish to do the calculations. Added note: {But straight conductivity after stabilization and cooling, with no fudge factor turned out to be the more accurate method}

22uS - .8 uS [initial water conductivity] - 3 uS [for 30 deg max heat soak effect]= 18.2 uS x 1.2 [fudge factor] = 21.84 PPM

Apparently this is in error even though ion to particle 'ratios' look about right.

Batch #2
20.5 uS [at finish @ 94.9 deg F] - .8uS [water] -3 uS [heat] = 16.7 uS x 1.2 [fudge factor]= 20.04 PPM
Stabilized for 8 days at 12.8 uS

Batches #1 + #2 averaged;
21.5 uS - .8 uS - 3 uS = 17.45 uS x 1.2 = 20.94 PPM

But I see that the average 'stabilized' PWT reading is more in accord with the AA..
Average = 12.6- .8 = 11.8 uS [x 1.2 "should be" 14.16 PPM.."is" 11.9 PPM]

You say:
12.6 uS is the conductivity figure you got.
If I subtract .8 uS for the water, I get 11.8 uS...pretty close to the 11.29 total PPM [as a 1 to 1 ratio] you came up with and accounts for why PPM is a little lower than conductivity. [That which was adding to the conductivity of the water wasn't silver]

There's something going on that I don't understand...like maybe relationships of conductivity to PPM aren't the least bit reliable?
I've got the sinking feeling that a PWT is totally useless where PPM is concerned.
So much for standard fudge factors too. [No reflection on you, Trem..it just didn't work for me.]

Reply from Frank Key
The answer is that you cannot use electrical conductivity to determine silver concentration. The relationship between ionic silver content and electrical conductivity is tenuous and highly unreliable. Anyone attempting to get reliable data from conductivity is just fooling themselves. This may be OK for a hobbyist but a commercial producer cannot rely on this measurement.

Our lab got a product sample made by a company that claims to be selling 20 ppm "colloidal silver" which they measure with a TDS meter. The product had 0.115 ppm of silver in it.

To get real results requires real equipment, hence my suggestion to find a used AA.

The Lab report......................My comments in italic.

Here are the test results for your samples from the ICP/AES.

These batches [#1+#2] were run totally plug n play / absolute neglect in a beaker and added together to form an average, allowed to sit for 8 days in clear glass. [Calculated" to be 21.5 uS - 3 uS [heat]- .8 uS [water] = 17.45 uS x 1.2 [fudge factor] = 20.94 PPM

Sample# 1-2

Conductivity {uS/cm} 12.6

Total Silver {PPM} 11.9

Ionic Silver {PPM} 9.68

Percent Ionic 85.7%

Sample #3

This batch was totally plug n play/ absolute neglect in a pint canning jar allowed to sit for 8 days in clear glass. It could have used a stir/reset sequence. My record:
Off at 17 uS @92.2 deg F dropping to 8.5 uS in 8 days. ["Calculated" to be 17uS -3uS [heat] -.8 [water]=13.2uS x1.2 [fudge]=15.85 PPM]

The result:
# 3
Conductivity {uS/cm} 8.5

Total Silver {PPM} 9.25

Ionic Silver {PPM} 9.12

Percent Ionic 98.6%

You can see that the conductivity to silver equation didn't hold water even using the very same water.

It says "something" and might be somewhat useful for comparisons but it's by no means accurate.

ICP/AES Measurements:

1. Each measured value was an average of three individual measurements. Each individual measurement was taken from three replicates of 10 seconds each. Total integration time per measured value (3 x 3 x 10 seconds) is 90 seconds.

2. Measured made using the silver emission spectral line at 328.068 nm

3. Calibration: blank ( 0.00 ppm) and 10.00 ppm - linear from 0 - 30.00 ppm (minimum)

3A. Measurement error (95% confidence) is less than: 0.05 ppm

4. Particles were removed from samples by application of 365,000 G-forces for 15 minutes.

Particles size distribution plots will be done in the next few days and the .pdf files will be emailed to you.

Francis Key, Principal Scientist
Colloidal Science Lab. Inc.
Westampton, NJ 08060
609.267.2065

It's pretty clear that using a meter is a hit or miss technique and every generator setup is going to give different results when trying to equate conductivity to PPM.
I wish it were otherwise, but it just ain't.
Anyone who uses "time" alone, as a standard probably isn't even on the planet.

You need to know "where" to start timing and you won't know that without some sort of instrumentation.

Ken