Well yes, you can, but ONLY if you're testing the carbonate hardness (a.k
.a. alkalinity) in your tank first.
Remember, water evaporates...alkalinity, salt, trace elements...do not evaporate.
If your tank stays at 8.2 with top-offs, and your alkalinity is at the correct range, then there's no need to add baking soda to top-off water. In fact you could end up putting too much alkalinity in there, and driving the pH too high (and then you'll be like the member in the thread above yours