Thanks, pitbull. Interesting stuff.
Just keep in mind that just because a substance is higher or lower than one's bedding currently is, that does not mean it's a good idea to add it to change the pH. Baking soda, for example, is sodium bicarbonate(from Wikipedia: "Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula NaHCO3" ). I have not seen any suggestion from any site to add that to the bins.
For my money, and worm's health, I will stick with using wood ashes from burning maple wood, ground egg shells, or garden lime. In Recycle with Earthworms
by Grossman & Weitzel, pg 29, I have also read that you can "grind up calcium based antiacid tablet and add a teaspoon every week or so." I have not seen that suggestion any other place, so I will leave it to you to prove its accuracy. I do know calcium carbonate- -Lime- - (CaC03) is alkaline and will raise pH.
Whatever you add, do so a little at a time, and monitor how the pH changes, AND how the worms do! I'd do it a little at a time, that's for sure.
What kind of pH measuring device are you using?