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Re: RO and pH



> Date: Thu, 25 Apr 2002 18:16:16 EDT
> From: Billinet at aol_com
> Subject: RO and pH
> 
> Two unrelated questions:
> 
>      1.  Does reverese osmosis by itself alter pH?

Yes, RO can alter pH.  IOW, the pH of the product water may differ from
the pH of the feed water.  Whether or not this happens is largely
dependent on the composition of the feed water.  It is thought that this
may be due to a boundary layer effect near the surface of the membrane.

If one is going to get into the nitty-gritty of RO you have to realize
that RO is not simply physical filtration with really small holes.  On the
ionic/molecular scale at which RO operates there are many complex factors
that come into play.  In general, the exact mechanism by which "things"
are transported across an RO membrane is very complex and not well known.

>      2.  Does the addition of "sea salt" alter the GH or KH?

This one is easier, and it's a yes.  If your "sea salt" comes anywhere
close to approximating the composition of natural sea water, then it
contains both Ca++ and HCO3-, and therefore by definition it will affect
both GH & KH.

> I say no to both.

Sorry, Bill...

--Bill