Hi Brad, The specs for the TDS-1 are probably a bit conservative.
My experience has been that the circuit is stable over time and, if you calibrate it at, say, 50 ppm or so, it will deliver reasonably accurate and repeatable measurements in the range in which we are interested. There appears to be very little zero offset in their design, so the low end readings are not as bad as you would expect from the accuracy and deviation specs. I suspect you can characterize a single unit much more closely than a randomly selected sample of them, and expect it to stay put pretty well. Nonetheless, it is *not* a universally accurate reading of true ppm, but only a relative reading based on conductivity. That point has to be driven home again and again, since some folks persist in not understanding it, while others persist in believing that we don't either just because we defend the utility of these devices. That said, a PWT is a much better choice for a reasonably priced conductance measurement. Mike D. Brad replied... > Well Bob > Here is the specifications section of the Hanna Instruments TDS-1 > Dissolved Solids Tester Meter with automatic temperature > compensation. The specification section is typed letter for letter > off the sheet inside the plastic storage case of my meter. Use this > information how you see fit. [Mike Devour, Citizen, Patriot, Libertarian] [[email protected] ] [Speaking only for myself... ] -- 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]>
