Maybe my science background can help here.
There are a few ways to demineralize water:
1) distill it
2) chemically treat it, then filter it
3) electrolyze it
4) evaporation/condensation
Distillation removes minerals, but leaves ions
which can be formed from gases in the air, like
CO2 forming carbonic acid. Further treatment of
distilled water by bubbling nitrogen (inert)
through it, forces out the gaseous ions giving
distilled AND deionized water. I only had to
use deionized water in experiments a few times.
(but I didn't work in science after schooling)
Water with minerals and ions in it will not be pH 7,
which is totally neutral, acid/base. If your water
is basic, like lime water, you could add an acid to
precipitate out the base, then filter the sediment.
Water that's a bit acid could be treated with a base,
in a similar fashion.
This is not as easy/good as distilling.
Using electricity you can remove metals and minerals
from water. But above a certain voltage, the water
itself breaks down into hydrogen and oxygen, so not
all minerals will be removed.
You can also use evaporation to get distilled water.
But it's a slow, low volume process. Basically
slooooow distillation, sometimes taught/used in survival
training.
Really for all practical purposes you can/should use
distilled water. You can get it at Wally World,
Rite Aid, CVS, grocery stores, etc. Just ask, if you
can't find it. Deionized water isn't necessary,
since it will pick up gases while sitting in a humidor/
humidifier, anyway.
BTW, you should only use distilled water in a clothes iron.
If you don't, over time you'll see the mineral deposits
around the steam holes, similar to the mineral deposits
at the base of geysers. They will eventually clog up
the steam holes.
Chemyst
