Hi!

or is fish respiration never great enough to create that kind of
imbalance/supersaturation in a soft, alkaline water?

Yes. Fish respiration produces negligible CO2 compared to diffusion with
the
atmosphere.

ok. that's good to know :-)

Either she's mistaken, or she forgot you don't have CO2. There's no
reason to
avoid aeration or surface agitation in a non-injected tank.

ok. thank you for the clarification! :-)

linda