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Old March 13th 07, 02:14 AM posted to rec.aquaria.freshwater.misc
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Default DIY In-tank pH meter

On Mar 12, 2:55 am, wrote:
On 12 Mar, 05:41, wrote:

I thought that this article might interest this group.


http://www.keepingfish.com/pageMain....d=DisplayArtic...


To quote:

The meter works by hydrogen ions passing through
the humid air until they are balanced.


There is no such animal as "hydrogen ions passing through the humid
air". What can be exchanged is pure water (think in terms of
distillation - evaporation/condensation) and carbon dioxide (plus
other gases, which won't change solution pH). Relying on CO2
equilibrium for pH measurements doesn't look like a reliable idea to
me - it may work only as long as CO2 is the only reason for pH
changes.

Best regards,
Borek
--http://www.ph-meter.infohttp://www.chembuddy.com


Thanks for your comments Borek. You make some excellent points.

I studied Chemical Engineering and have some understanding of what you
are saying. What I do know is that the pHs in the two bodies of water
seem to reach equilibrium. My pH meter seems to work. I was just
speculating about the actual mechanism. Perhaps it is the CO2 gas.

Thanks again for your discussion.