Re: water question

[wrisch@uclink4.berkeley.edu (Lisa Wrischnik)]

Hi gang,

Bob said:
>
>Ion exchange resins have a sodium-containing salt that readily gives off the
>sodium and binds calcium, magnesium, and other heavier metals, in an
>"exchange" process.  While the water tests soft for GH and KH, and acts
>"soft" in the presence of sudzy things like soap, it may not be suitable for
>some soft water fish.  Most of them will do quite well in it, but some are
>sensitive to saltiness, and may not like this water much.  Years ago, I heard
>of a DI unit that had a second stage, which electrically removed the sodium
>compounds, giving a water quality as good as or better than RO, but I am not
>sure they are still available.
>
You could also just get a DI unit that exchanges cations such as Ca+2 and
Mg+2 with a hydrogen ion (H+) and anions (like nitrites and Cl-) with a
hydroxide ion (OH-). You end up replacing all the "bad" ions with,
essentially, the components of water (H20). This is what I have and it
works pretty well (I charge up the resins every few weeks or so using
hydrochloric acid (sold as muriatic acid for pools) or sodium hydroxide
(lye).

I know that companies like "Culligan" will set you up with a water softener
that replaces cations with sodium, but I have been told that these
companies can also set up a DI system that replaces with H+ and OH- (the
guy I'm married to has one of these to give him DI in his lab). May be
worth the initial investment for some people (I think maybe $300 to get
started and then paying for the replacement tanks every so often -
depending on your local hardness conditions).
I can find out more if anyone really cares ;).

Lisa