[sci.electronics] Digital Ph meters

richard@gryphon.COM (Richard Sexton) (01/05/90)

In article <5888@ncar.ucar.edu> cruff@handies.UCAR.EDU (Craig Ruff) writes:
>In article <5985@alvin.mcnc.org> bing@mcnc.org (Carter E. Bing) writes:
>>         I saw one of these the other day for about $69 (which
>>   is to steep for me) and I was wondering if anyone has purchased
>>   one? Are you pleased with it?
>
>I picked one up from Edmund Scientific for $89.  It seems to function
>as advertised.  I calibrated it with a buffer solution (pH 7.0 @ 25 deg. C)
>which is close enough to conditions in my aquarium to provide confidence
>in the readings.  I'll probably use it more often than I used chemical
>indicators with better results.  It only takes a few seconds to get
>a reading.

Ron Harlan sells these things for $65; he also has hardness meters
(which are actually conductivity meteres) for the same price. It's
actually pretty easy to talk him down to $50 :-)

And now the the reason for the massive x-post. Does anybody know
if it's possible (and feasible) to build meteres for chemicals
such as Ammonia, Nitrates, Phosphates, Iron ?