Pet Forum / Aquaria / General / October 2008

400 ppm what?  Ca?/total hardness?

You would need zeolite or an ion exchange resin to lower that.  And,
with these I would use potassium chloride instead of sodium chloride (or
a 50/50 mix of potassium chloride with sodium chloride to recharge the
zeolite/ion-exchange-resin ... there are other ways--google will show
you these.)

Carbon will not influence ph, at least not much ... to lower ph you will
need an acid buffer to add to the water and lower ph.

You could consider exchanging part of the aquarium water with deionized
water--this would be fast, safe and easy--do it in increments--maybe 25%
of the aquarium water at a time.

Regards,
JS

Reverse Osmosis would be a way to go to remove the hardness from your
drinking water ( and everything else). It's not a cheap method but not
overly expensive in the long run.
http://www.freedrinkingwater.com/

That being said is there a particular reason that you want to lower the
hardness in your drinking water ? The PH isn't bad and hardness in drinking
water isn't known to be bad for you...in fact you get a little calcium from
it.
http://healthvermont.gov/enviro/water/hardness.aspx

HTH,
Bob

A cheap way to remove calcium/general-hardness from water is plants.
They use up these elements as the build plant material ...

A body of water growing algae and plants outdoors will eventually become
soft.  A childs' swimming pool, a large-old aquarium, etc. can be
employed.  A bit of potassium, phosphorus and nitrogen should get the
process accelerated and to progress at a good rate of speed, a general
test kit will let you know when the water is ready ...

Regards,
JS

You would be better off buying a Heavy Metal water purifying removal unit,
used for discus fish. If you intend to use as drinking water.