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Re: Re: measuring calcium and magnesium
>>Date: Thu, 09 Jul 1998 02:55:04 -0700
>>From: Steve Pushak <teban at powersonic_bc.ca
>>
>>The issue IS:
>>"what units should test kits use?"
>IMHO, major test kit manufacturers (LaMotte, Hach, Merck, Hanna) don't
much care
>about what a few dozen aquatic plant enthusiasts think they need, especially
>since the test kits they already sell satisfy those needs with a small
amount of
>arithmetic on the part of the user.
Merck cares. Maybe it's only a chance but it does. Their titrimetic tests
give you the result in:
* German degree
** millimoles
*** equivalent ppm of CaCO3 (for hardness of course!)
you can READ ALL these results DIRECTLY from the graduated scale on the
sirynge pipette. WITHOUT making ANY calculation. Only the Mg++ content is
calculated as difference (easy operation, I SUPPOSE!) between TH and Ca++
contents.
The carbonate and Ca++ content tests have a resolution of 0.1 mmol/l (0.2
german d), while TH tests are 2:
* one very precise with a range from 0.25d to 5.6d and resolution = 0.1d.
* one with a bigger scale from 0.2d to 20d with the same resolution of
0.25d as the other ones.
They are expensive but consider that each one makes AT LEAST 300
misurations and so at the end they result to be cheaper than other tests
made for aquarists (e.g. Tetra) and surely more precise.
If anyone is interested, I'll post the code list for these tests. You may
consider to visit Merck web too (http://www.merck.de).
Sincerely,
Luca Specchio
PS: if anyone from MErck sees the msg... please make a BIG discount on the
next order... ehehehh ! :-)))
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