On Thu, 24 Mar 2005, Mike Hord wrote:

>> Opinions?  Next I'll test the filtered de-ionized.
>
> The filtered, de-ionized water comes back at approximately 1.6 MOhm
> for the same configuration.  It's falling fast, too; after 2 minutes or so,
> it's now down to 1.2 MOhm.
>
> The reading on the filtration system is 18.2 MOhm*cm.  I suspect the
> difference is due to the fact that I didn't flush the system with the
> "purer" water, coupled with the fact that I flushed it through brass
> fittings, might have something to do with that...again, this is a pretty
> crude experiment.

You may be seeing polarization. Conduction in an electrolyte is covered 
in basic university physics. In general one does not measure an 
electrolyte with a dc current, one swaps the polarity all the time to 
prevent electroplating and other effects.

Peter
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