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Re: Calcium Hardness & Alkalinity

"A M Moore" <andy at ascot_u-net.com> wrote Sat., Feb. 14
>Subject: Calcium Hardness & Alkilinity
>Could someone explain the difference between Calcium Hardness & Alkalinity.
>Do they correspond with each other in some way ?
>One of my Tetra kits (KH) reads Carbonate Hardness ? Is this the same as
>Alkalinity or Calcium Hardness ?

The Tetra kit reads GH, general hardness, which is a measure of calcium and
magnesium ion content.  The other reading, KH (carbonate hardness) is
really just a measure of alkalinity---roughly how much acid it takes to get
the pH of the sample down to around 4.  Hard water has mostly calcium and
magnesium bicarbonate, and gives high GH and KH values.  Hard water that
has been softened with an ion exchange resin is mostly sodium bicarbonate,
and this will give a low or no GH value, but still a high KH value.  The
tap water where I live is just like softened hard water, and I wonder what
chemical processes underground produced it.  It has no measurable calcium
with the LaMotte calcium test kit, and no measurable GH with the Tetra kit.
It has 9 degrees alkalinity (KH) with the Tetra kit, and the pH out of the
tap is 8.5.

Paul Krombholz, in central Mississippi where you can't have basements
because your house would float away.