On Fri, 30 Jun 2006 03:51:38 GMT, Cindy wrote:

My tapwater pH is 7.6.
The water that comes out of the RO filter is 6!
No wonder I can't keep my pH up. Do RO filters normally make the pH that
much lower?

Cindy


Don't worry at all, this is a normal pH for RO. RO water has very
little dissolved solids and minimal buffering, hence *tiny* increases
in hydrogen ions from any acid present in traces (eg just dissolved
CO2) will cause significant drops in pH. Because there is very little
acid actually in the water the pH is buffered immediately you put it
in the tank or mix it with salt, sal****er of course contains lots of
buffers and it is *those* that stabilise pH. Look at alkalinity, Ca
levels, how much kalk you are adding - if your pH is low it suggests
in tank buffering is deficient. The added RO water will make no
difference in itself.

Steve