I use this in our pool to raise the alkalinity (and sometimes ph). Especially after a really good rainfall. It works! Start with a small qty in relation to the size of your pool, test again, and adjust as necessary. Works like a charm, and it’s pure. Don’t even bother with overpriced pool supply store products that are full of extra nasties.
We also use this in every laundry load to keep everything deodorized and fresh smelling. Highly recommend!