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pH meters

Hi folks,

GB has been talking about pH test kits, etc. recently, and I've got to add
my support on the electric pH meter camp.  

Yes, those bulbs can be fragile, but most of them come with little cages
these days to protect the bulb.  Yes, they have to stay wet, but just stick
them in a little vial (doesn't everyone have little vials somewhere in
their homes?), and it's not a problem.  Yes, they are expensive, but it's a
one time expense, and heck, those LaMotte kits are expensive too!

A few words about pH calibration:  you need to have not-too-old calibration
buffers (i think less than two years is ok).  The best way to calibrate is
to have three solutions, one at 4, one at 7, and one at 10.  A good meter
will calibrate like this: stick the electrode into 4, hit "set", rinse it
off, stick it into 10, hit "set", and then it has 4 and 10 in its memory.
Then stick it into 7 and see what the reading is - ought to be 7, or real
close to it anyway.  This way, you can confirm that your meter is working
properly.  You'll need a small beaker and water bottle with pointed nozzle
to rinse off the electrode properly.

We have this set up at work (I work in molecular biology), and we do a lot
of stuff (buffers for cell lysis, dialysis, etc.) that requires pH-ing.  If
I had the bucks for it, I'd get one of those for my tanks, too.  Right now,
I'm using test strips - also lifted from work (ha ha), just stick them in,
compare to a chart, and is accurate to .5 units (which is good enough for

And, fwiw, the temperature thing is not necessary for aquarium purposes.  I
suspect that it is primarily for use with Tris-based buffers, which can
vary a LOT (I think it covers a range of at least 1, maybe even 2 pH units)
depending on temperature.