If they are out there I've never seen them. Maybe somebody carries a research grade perhaps. But personally I've not seen them.
I have used Pinpoint Ph monitors for over 7 years, and it is one piece of equipment I would NOT be without. (Ditto for my Medusa heater /chiller controller.)
Anyway, HTH
Hermit
[ October 21, 2001: Message edited by: Up North Hermit ]