RE: Ph meters

[Ken Simolo <Simolo@chem.chem.rochester.edu>]

I sent this to the list back in January.

I would recommend the silicon chip sensor pH meters. They can be 
stored dry and the electrodes are good for 10,000 - 20,000 readings. 
Most of the standard gel pH electrodes (the kind found in most of the 
small hand-held pH meters) last for 6 months to 1 year and then you 
have to replace the whole meter.  The best price/performance that I 
have seen are at www.phmeters.com - I have now used one of their's 
for 18 months with no problems.  They came highly recommended by a 
salesman who only carries standard hand held pH meters so he was 
actually losing business by recommending them!  The electrode is 
stored dry which is a very nice feature.  For measurements, all you 
need is 1 - 2 drops of liquid.  The extra $25 to get the model 125 
(if I remember correctly) is worth it because you get 3 point 
calibration capability among other things.  During the last 18 
months, my meter has drifted by only 0.1 pH units.  The only negative 
is their cost but they pay for themselves in just 10 - 15 months as 
compared to gel electrodes.

Ken


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