[MarineBrat]

...cyanuric acid is often used as a disinfectant for swimming pools.

No, it's used as a "binding agent" for chlorine. Most pool store people (who are out to rip you off BTW) call it "conditioner."

[PennsylvaniaMom]

No its not a binding agent. Cyanuric acid 'stabilizes' chlorine so that it doesn't burn off quickly in bright sunshine. It can be added alone (to use with non-stabilized chlorine) or it can be added into the granules/pucks by the manufacturer and sold as 'stablized chlorine.'

I don't know where you shop, but most pool stores aren't going to stay in business by ripping off customers. The products sold by pool retailers are stronger mixes than what you can get in a 'big box store.' For example, pool shock. If you buy it at Wally-World it is under a 50% mixture...pool stores sell at 68 and 78% calcium hypochloride. You pay more for the stronger product and the fact that it has to be hazmat placarded to ship to the pool store. Wal-Mart can ship the weaker blends on the same truck as your Rice Krispies...just fyi.