Hi Ivan, Robert and other list members: FYI, I have also obtained a TDS-1 unit. My unit, according to the supplier, has been calibrated to read PPM. The unit has been calibrated before being shipped to me with a solution of 2 uS to read 1 PPM on the unit. (This appears to match your comments Ivan)
Naturally the unit reads in uS, but the readout is in PPM. I have compared the reading with a conductivity test (home made gadget) and the reading appears to be very close. Therefore, it is most important before purchasing one of these units to know: 1.- What the unit provides as a reading (i.e.: ppm or uS) 2.- What is the accuracy of the unit. 3.- Where to obtain the solution to calibrate the unit. This is my opinion on my unit. I cannot comments on other units. Gaston ========================================= ----- Message d'origine ----- De : Ivan Anderson <[email protected]> À : Silver-List <[email protected]> Envoyé : 13 avril, 2000 00:55 Objet : CS>Hanna meter > Well there you go, > (Are you there ole Bob) > > It just shows you the unreliability of using conductivity as a measure > of concentration (ppm) of colloids, unless they are used within strict > parameters. > Although, if Robert uses his PWT in the same manner every time, then > the chances are that he will have good correlation between his reading > and the actual concentration. > > The relationship between silver IONS (Ag+ as distinct from colloid > particles) is > 1.76 at 5ppm and 1.78 at 20ppm, so lets say 1.77. That is the uS > reading times 1.77 is the concentration in mg/L (ppm). 1.77ppm / uS or > 0.57uS / ppm. > In full... 0.57 uS cm^2 / mg. > > So 5ppm will read 2.8uS > 10ppm will read 5.7uS > 15ppm will read 8.5uS > 20ppm will read 11.3uS > > The above is true for a silver colloid that is made with some regard > to current limiting (density) and minimal sludge inclusion, AT THE > TIME THE POWER IS WITHDRAWN FROM THE ELECTRODES. > > Many will find that the conductivity or ppm reading will rise as time > passes, even to a point where the reading is double the actual silver > concentration. > The uS reading of well made CS seems to rise until the ppm equals the > uS reading and remains stable at this point. > > The rate and the amount this occurs can be some indication of the > quality of the colloid, that is, the amount of uncharged particle > inclusion, and the amount and rate of flocculation or particle > aggregation. > > Ivan, > > ----- Original Message ----- > From: "Robert Dohr" <[email protected]> > To: <[email protected]> > Sent: Thursday, 13 April 2000 10:35 > Subject: Re: CS> Hanna Meter > > > > Greetings Seekers; > > Regarding Hanna Meters TDS & PWT. I have the PWT #98308. I know Ken > (Coyote) > > has the TDS1. We have been comparing notes on batches made using the > same CZen > > generators. As for me I spoke to the techs at Hanna. They said that > with the > > PWT which measure conductance in us/cm, to convert to PPM I should > divide by > > two. I made a sample batch of CS which measured 25.5 us/cm and sent > it to the > > lab at CSPro systems to have it tested by PhotoSpectrometry. The > results came > > back at 15 PPM. That would be 59% of the measured reading. This is > how I now > > measure all my batches. Ken can tell you what fudge factor he uses > for his > > TDS1. How about it Coyote? > > NAMASTE' > > Beldohr > > > > > > > > -- > 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] > Silver-list archive: http://escribe.com/health/thesilverlist/index.html > List maintainer: Mike Devour <[email protected]> >
