Hello Robert, I agree very closely with your information. We market the Hanna PWT and tell our customers the meter reads correctly on samples we have had analyzed by the atomic absorption method but if they want to follow the information given by Hanna, to multiply the reading by .55 to get their reading. In any case, it's right on or 45% high. I really don't see this as a critical problem since we're speaking only of a few parts per million. This is briefly covered on our PPM page at our web site. We do not mention the 55% effect since we are content to accept the AA test as being accurate. However we do point this anomaly out on the instruction sheet we provide with the PWT.
What is important is the fact a person can tell from batch to batch what they have made. The PWT is the best low cost solution to making reliable CS from one batch to the next and confirming the results. The TDS-1 is unacceptable for measuring PPM. Trem www.silvergen.com Constant Current Colloid Generators ----- Original Message ----- From: Robert Dohr <[email protected]> To: <[email protected]> Sent: Thursday, April 13, 2000 3:06 PM Subject: Re: CS> PPM > Greetings Seekers; > Ivan, our numbers are similar (.59 to .57) but I think you may have them > backwards. The instructions from Hanna and what my lab results confirmed was > .59PPM/us. or take the reading in us/cm times .59 to get PPM. In my case > 25.5us/cm = 15 PPM. per lab test. Also the us/cm will drop with time for the > first 10-12 hrs, not rise. This appears to be due to the CS dispersing > throughout the DW. Immediately after making a batch the CS is concentrated > around the ion path between the electrodes. A reading taken at this time will > be high and erratic. After sitting overnite the reading will be lower but > stabile. After this initial dispersion the reading should not change futher. I > have CS that is now several months old that still reads within 1 us/cm of when > it was made. As for accuracy my PWT measures in .1us/cm up to 99.9us/cm. I > calibrate it using a solution from Hanna that measures 84us. It comes in small > pouches that you tear open and insert the meter. Use once and throw away. > NAMASTE' > Beldohr > > ____________________________________________________________________ > Get your own FREE, personal Netscape WebMail account today at http://webmail.netscape.com. > > > -- > 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]> > >
