In that case would you advise the use of a CO2 diffuser instead of a PH
buffer.? Could baking soda be used directly in the water without
endangering
the water's balance?

I've used baking soda to raise the gH and pH when needed, but never added
more than 1 tablespoon.


Lime (calcium carbonate): Same effect as Baking Soda, also raises GH

I'm not sure... I would dare to say not to use it until you hear from some
of the more intelligent ppl here, not me... I'm not smaart... :-)