Originally Posted by Gregcoyote
Baking soda would raise your KH
and your PH some. Not lower it. It is usually recommended that you bake it for a few hours to drive C02 out of it first. Not recommended for adjusting PH.
Actually plain baking soda will slightly drop your pH. If you bake the baking soda, which in turn drives out the co2
, it will have the affect of slightly raising your pH.
An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com
"Baked baking soda" - "Adding on the order of 0.5 meq/L of alkalinity increases the pH by about 0.3 pH units immediately upon its addition."
"Regular baking soda" - "Adding on the order of 0.5 meq/L of alkalinity drops the pH by about 0.04 pH units immediately upon its addition."