Re: PH crashing up?

["Alan Whitten" <caw18 at bak_rr.com>]

> Date: Sat, 26 Apr 2003 04:18:05 -0400
> From: Chuck H <grendel at usit_net>
> Subject: Re: PH crashing up?
>
> C. Alan wrote:
>
> >The water I am using is a mixture of RO water, and tap water.  I add a
> >little baking soda, Kent's RO right, and some Kent's PH control
> >Minus.  After mixing for about 24 hours, my change out water has a Ph of
> >around 6.5, A GH of 2, and KH of 2.
> >
> >What is happening is this:  I add my mixed water, and the PH drops down
to
> >around 7.  Within 24 hours it will rise up to around 8.4!  I tested the
> >KH, and it is still at 2 or less in some cases.  So what is driving the
PH up?
>
> What you're seeing is called "pH rebound" or something close.  Basically,
> the buffer in your tap/tank water is strong enough to throw off the
effects
> of the softer water.  I have a nice explanation of what is happening
> chemically stowed away somewhere.  I'll try to find it and send it to you
> if one of our more chemically enlightened list members doesn't feel called
> to elaborate.
>
> Are you cutting your tap water with RO water to drive hardness and
> alkalinity down?  If that's the case, I don't see why you would add bicarb
> and the Kent stuff to the change water.  Just add enough straight RO water
> to your tap water to get the hardness and alkalinity down to where you
want
> it.  For the water already in the tanks, do a few changes with straight RO
> to gradually get parameters down.  There's no need to mess with all those
> chems.
> - --
> Chuck Huffine
> Knoxville, Tennessee
>

I am cutting the tap water with RO water to reduce the amount of Nitrate in
my water.  I live
in an area with a lot of farming around it, and in the summer time when the
water tables get low
the nitrates can get has high as 50ppm.  Right now, my nitrates out of the
tap run about 20ppm.
The tap water runs about 3 degrees of GH and KH.  I basicly use the tap
water to stretch my RO
water supply.
--C. Alan