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Re: TDS calibration
lwb wrote:
>
> Hi,
>
> Many of the list members have extolled the virtues of having a TDS meter
> in the fish room. Thanks, I'm convinced. I mix the really hard water
> here with rain
> water and I'm concerned/curious as to what the hardness comparisons are
> when I try different concoctions.
Be more concerned that you aren't shocking your fish, Lyle, as the tds can
change a lot in a tank for a variety of reasons, such as gravel dissolving,
food rotting, fish excrement, etc.
>
> Those of you that bought one, did you also buy the calibration fluid and
> if so, which one? There are several listed. I could ask the company but
> I thought I would throw the question out here first. Thanks in advance.
Precise calibration fluids are only needed for very accurate scientific
measurements. We are more concerned with relative values and rough figures
are pretty adequate, since the instruments rarely drift anyway. If you want
to check yours, a solution of 10g of CaCl in 100 cc of distilled water
should read 100 g/l (010 on the inexpensive Hanna meter that reads to the
closest 10 ppm). The same amount of NaCl probably will read about the same,
and pure salt is easier to obtain. The distilled water should read 000.
Calibration fluids are vital for the pH pens, as the delicate porous probes
get contaminated and can drift serriously under different storage
conditions. Keep the tip wet to avoid this, if possible. The conductivity
meters are made with far more rugged probes, and the electronics of most
I've used seem very stable.
Wright
--
Wright Huntley, Fremont CA, USA, 510 494-8679 huntleyone at home dot com
There are two rules for success in life:
Rule 1: Don't tell people everything you know.
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