So you want to make a bulk quantity of baking soda and water? As a suspension? OK, first of all, baking soda is soluble in water, so you will have to use much more. You'll have to figure out how much more that is. You can look it up, or you can do the experiment yourself, with careful notes. Then, you want a suspension to be stable. OK, you've seen things like that -- jelly or other gels. Which of those do you have access to, that fit your application?