Keith.Hand at wmc.com.au
I'm not quite sure just how you figure this but 1) Aquarists have been using
bicarb for years with plants without this dangerous increase in pH 2) Several
of the plant "religious", recommend to those w/o enough carbonates in their
system to add bicarbonate to help provide some buffer (when they are adding CO2
to the system.) What you're suggesting just doesn't happen. I've seen
aquarist all over the east coast of the US, in very soft buffering (KH,
carbonate hardness) areas use it with quite decent results. Never have they
reported these sorts of results. If you can pull up a memo from George Booth
(and supporting data) :-) Soda ash (Na carbonate) as Peter stated earlier
will pull the pH up fairly high, but that has nothing to do with
photosynthesis.
You can find some of this info on the Caltech site and I'm sure some of the
other material at the AGA site. It's been awhile since I looked at it but if
you dig I'm sure you can find it and the doses recommended.
gw Lange
Rainbowfish Study Group