Jim & list, I have strong reservations for mathematical "calculations' of how much silver 'should' be in our CS. While it's interesting technical background, I'd like to offer my reasons why; please don't take offense if I play the 'devil's advocate' for a moment...
Your disreguarding of the silver 'sludge' that does in fact accumulate at the cathode is your big undefined variable; this is not a linear effect, either... by the time that your CS wil test in the neighborhood of 20PPM, the amount of silver plating out is a significant amount... You'd have to end up paying a lot of lab testing fees to begin to understand what type of a 'fudge factor' to use for a given electrode geometry, tepmerature, voltage, etc.... and if the electrode gerometry changed, you might need to recalculate again... Bob Lee offered an excellent dissertation on calculating the number of electrons allowed to flow through the system, in another approach to the 'calculated' CS PPM... but gas evolution at both electrodes must also be taken into consideration in such an approach, and that consumption of electrons was never quantified... A calibration technique for the Hanna TDS1 & other models has been repeatedly discussed; once you have lab results back, you can calculate closely enough for most CS user's purposes. For example, I believe it was Fred Walters who reported taking readings of 20PPM to 22PPM with his TDS1 on about 3 samples, then sending them off to the lab. The lab returned about 25 to 28 PPM acording to their testing, as I remember. (Hope my memory serves me well... <g>) This is a good indication of the correction factor, I'd say; I can work with it. Someone else stated something to the effect of, "the TDS1 only reflects the amount of positively charged IONIC silver particles" , to which I say, HOORAY! - especially since it is reported that positively charged ionic particles of silver are at least 300 times as effective as the non-ionic form, and even more so when compared to the effectiveness / toxicity against single celled organisms, in comparison to some silver compounds... (Please follow the link to the 'Brittish Columbia Ambient Water Quality Criteria For Silver' on this page for further info...) http://web.idirect.com/~showcase/althealth/csilver.htm Jim wrote: > > I have been doing more test runs experimenting with CS than I care to > spend money on reliable ppm testing. So I needed to come up with a way > to determine an approximate ppm so I could tell if a test run was worth > continuing with, or worth sending in for tests. > > I am able to measure in a "NOT MORE THAN" way which is very reliable. > With a grain scale I can weigh my electrodes, make a run of 2 liters, > and weigh once again. > > This tells me exactly how much silver came off the electrodes, but not > how much stayed in suspension, so I at least know I am not more that the > resulting number. > > As ppm is milligrams per liter, if I lose 0.6 grains of silver in 2 > liters of water: > > 1 grain = .0648 grams > 64.8 milligrams x 0.6 = 38.88 milligrams > 38.8 / 2 liters = 19.4 milligram per liter (assuming no fallout or > plating) > > So the above example would give me a "not more than" 19.4 ppm. > > Should be a near perfect test if averaged over enough liters of solution > for those who make sub-colloidal sized particles. Will give those who > make large particle cs with some fallout or plating at least a benchmark > of "something less than" so as not to assume too high a ppm. > > Grain scales are cheap, measuring is easy and foolproof. I would expect > a much better assessment than the use of a TDS for everyone, as at least > one end of the range is an absolute! > > Jim I'd like to see lab verification of this 'weigh the loss & calculate it' approach before I felt good about how close it will bring us to what's really in there... One of the correlaries to Murphy's Law states, "If everything seems to be going fine, you've obviously overlooked something" .... are there other details to take into consideration in this approach? Hope this provides food for thought... and I hope you can afford enough lab testing to validate this approach, or not , as the case may be. I'll be very interested in any further info. Be Well! Bruce -- 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: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the subject: line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
