I buy bags of A and H baking soda (sodium bicarbonate) at Costco as needed to control alkalinity. The bags are big, cheap and go to great length to extol the virtues of their product for controlling pH and alkalinity in pools. From time to time I've had to buy soda ash at pool stores or home centers to raise pH knowing I was just buying expensive sodium carbonate under some name like PH UP. Anyway, I noticed that WalMart sells A and H Super Washing Soda which says "Ingredients: Sodium Carbonate." Period. "Pure and Natural since 1874. 100% Fragrance and Phosphate Free". Curiously, there's no mention of using this stuff in pools like there is on the sister product. Their web site is useless, but they "welcome your comments and questions". So I call the 800 number, where, after consulting with someone else, the woman comes back and says "we don't recommend using Super Washing Soda in swimming pools". I explain the apparent contradiction that their main product gets clear instructions for how to use it in pools, but this other one, which appears to be a common pool chemical isn't recommended. She says, "well, we haven't tested it for pool usage". A pretty bogus answer.
I think there is some marketing arrangement going on whereby they are prevented from competing with branded pool products. Has anyone used this stuff to raise ph?