Advice? Alkalinity dosing question

I've used both. Lately I've been using sodium bicarbonate and have no issues with pH. The only reason I switched is BRS recently raised prices and I ran out of soda ash. Decided to just grab some Arm & Hammer baking soda from the kitchen cabinet instead. Note that a 4 lb box of baking soda is only $3.19 at Hy-Vee vs 7 lbs for $23 on BRS.

You can also make your own soda ash by baking sodium bicarbonate in the oven. Soda ash is good if you have low pH issues (for example if you're running a calcium reactor or have poor ventilation). Baking soda is pretty neutral on pH so that's why people recommend it if you're also dosing kalk (which raises pH).

Also note that the recipes and dosing amounts differ between the two. You mix roughly twice as much soda ash in your solution compared to baking soda. However, you then dose at about half the rate you would have with the baking soda solution. I've always assumed the solution difference is due to solubility but I'm not 100% sure on that.