Quote Originally Posted by kreeger View Post
Try looking for Beckman Zeromatic model. Again the accuracy as someone mentioned is in the probe itself. Get your buffer solutions to calibrate and you're set.
When I was doing photo chemical analysis in the 80s under military spec requirements, we used Beckman pH meters as the standard. Lots of Beckman stuff on eBay cheap.
http://www.ebay.com/itm/Beckman-Zero...item3cba92e07b
And, in best practice you leave them running all the time with the probe in a proper buffer solution.
Thanks for the suggestion. I'm realizing that I can't go cheap on the probe, so I'm looking at a refillable model from Thermo Scientific. Interesting that the Beckmans are cheap on eBay. I'd guess those meters were well north of US$1000 when new.

Mark Overton