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Re: GH Chemistry
> Subject: GH Chemistry
> Last night prior to a water change I measured KH=7, GH=0, in the tank, using
> Aquarium Pharm. test kits. I use DI reconstituted with Kent's R/O Right
Why? There are cheaper ways of doing it, and you would (if you
used them) know what was in your water.
> one teaspoon per 10 gal which sets conductivity to 250 uS/cm, as measured
> with a meter at work.
Water conductivity isn't something most people worry about.
> I also add one teaspoon baking soda per 10 gal. I
> switched to reconstituted DI one month ago (2 20% W.C. thus far). I brought
> a tank water sample to work today and measured conductivity at 330 uS/cm,
> which from my research looks OK, correct?
> I have spent some time at the archives and The Krib, and understand why GH
> and conductivity don't correlate, and that GH test kits typically only
> measure the Ca/Mg concentrations, not all ions present,
They are _supposed_ only to measure Ca++ and Mg++. That is the
definition of "hardness".
> but that being the
> case, wouldn't the test kit give me some indication if there were Ca and Mg
> in the sample?
I'm not sure I understand the question properly, but if you mean:
"Could the GH test kit be used to detect Ca++ and Mg++?" The answer is
"Yes". If there were only a few ppm there, though, you probably wouldn't
notice it, as the colour change of the test would occur when the first
drop of reagent was added. You would have to dilute the reagent to stand
any chance of measuring low Ca++ and Mg++.
From your observations I infer that there isn't much Ca++ or Mg++
in "R/O Right".
Paul Sears Ottawa, Canada