> My pH strips, some half dozen in a range from lowest to highest pH, used
> to be OK, at least for my purposes, but lately have been giving me
> trouble... Maybe they're just old? (About 15, 16 years -- seems quite
> young to me, but go figure.)
>
> Lately the color you match with the label color to read the
> pH doesn't stabilize, but keeps going on up (or down as the case may be).
> On silver testing papers they say take the reading at so and so many
> seconds, but there's no advice about that on these.
>
> Any suggestions?
>
..Judy, your pH strips are definatly to old, as is indicated by the
unstable colour. I think investing in new pH paper test strips is cheaper
than a pH meter when buying 2nd hand (if available ?) you must be sure to
obtain a good pH electrode (can break easily..know from
experience..;-)..), and you also need three calibration solutions (pH 4.0,
7.0 and 10.0)
> Thanks in advance,
>
> Judy
>
>
Cor Breukel
http://ruly70.medfac.leidenuniv.nl/~cor/cor.html
"The Infrared Gallery"
http://ruly70.medfac.leidenuniv.nl/~cor/ir-gallery.html