Look at the active ingredient in that expensive pool chemical to raise the level in pools. . . I have. It's Sodium Bicarbonate. Baking Soda. Just a lot more expensive!
I use baking soda in quantity for cleaning jobs so I buy a big bag of it I find in the pool isle of the local store.
Also, if anyone wants to use baking soda as a cure or in food, they should buy non aluminum baking soda. Here is a link to get it at and lots of other great product offers (One doesn't get a commission from the site, unless you want to put me down as the one who referred you. Then they will give their customers ten dollars credit for every referral.)
http://www.vitacost.com/productResults.aspx?x=23&y=18&ntk=products&ss=1&Ntt=baking%20soda