Need Help - Name of Chemicals Used in Water Hardness Test Kits - Buffer + Calmagite + EDTA type

[m***@yahoo.com]

Need Help - Name of Chemicals Used in Water Hardness Test Kits -
Buffer + Calmagite + EDTA type
=============================================

I live in a country where Water Hardness Test Kits (smilar to
one sold by Hanna Instruments) are not available. With some
difficulty, I can import the chemicals which are used in this
type of kit. Out of total 3 chemicals, I know the name of 2, which
are:

Calmagite Indicator

Ethylenediaminetetraacetic Acid

Can some member please help me identify the 1st Chemical,
which is generally referred as: Buffer and also suggest the
concentration of chemicals (w/w basis), which I should use
to make the solution in Distilled Water.

Thanks

Frank Gatta

[David Stone]

Post by m***@yahoo.com
Need Help - Name of Chemicals Used in Water Hardness Test Kits -
Buffer + Calmagite + EDTA type
=============================================
I live in a country where Water Hardness Test Kits (smilar to
one sold by Hanna Instruments) are not available. With some
difficulty, I can import the chemicals which are used in this
type of kit. Out of total 3 chemicals, I know the name of 2, which
Calmagite Indicator
Ethylenediaminetetraacetic Acid
Can some member please help me identify the 1st Chemical,
which is generally referred as: Buffer and also suggest the
concentration of chemicals (w/w basis), which I should use
to make the solution in Distilled Water.

It's typically a mixture of ammonium chloride in ammonium hydroxide,
with magnesium-EDTA. The recipe in the standard water/wastewater
method specifies:

16.9 g ammonium chloride and 1.25 g Mg-EDTA in 143 mL of conc.
ammonium hydroxide, diluted to 250 mL.

If you know your samples will always have some Mg in them, you
may get away with a pH 10 sodium hydroxide solution, but the pH
will obviously start dropping as you perform the EDTA titration.

Does anyone in your country sell or import aquarium test kits,
though? You can get both carbonate and Ca-Mg hardness ones...