I've been dosing Two Little Fishies two part, but I am almost out and am planning on making my own 2 part using the recipe from Randy Holmes-Farley. For the alkalinity I'm going to use baked Arm & Hammer baking soda, but I was just wanting to make sure the 12 pound bag that I got is the same as the little boxes. The bag says that it is pure baking soda and lists sodium bicarbonate as the only ingredient so I'm fairly sure that it is. The only reason I'm questioning it at all is because the packaging is listing it mostly as a pool chemical, but I'm guessing that is due to the quantity of it.