Anne Marie's Chemistry Blog(http://chemistry.about.com/b/2007/11/10/substituting-baking-powder-and-baking-soda.htm).
Using Baking Powder Instead of Baking Soda
You need to use 2-3 times more baking...
Since the main ingredient in baking powder is bicarbonate of soda (baking soda), you may be able to use baking powder, depending on what the recipe is.
yes, it has nothing to do with cleaning your pool though . soda ash raises the level of PH in you pool, baking soda does the same but it actually raises the TA (total alikinity), thereby stabalizing...