Adding dry acid

[rsillaway]

Do I need to leave my saltwater system on when adding dry acid to my vinyl lined above-ground pool?

[chem geek]

You need to have the pump running, but the saltwater chlorine generator can be on or off since that doesn't matter. However, dry acid adds sulfates to the water and that is not good for saltwater chlorine generators or for plaster (not your situation) or stone/concrete hardscapes. You should consider using Muriatic Acid instead.

With dry acid, I'd pre-dissolve it in a bucket of pool water. Pour very slowly over a return flow with the pump running and then lightly brush the side and bottom of the pool where you added the acid to ensure thorough mixing. Acid is damaging to vinyl so you don't want it pooling at the bottom. Once mixed, however, it stays mixed.

[rsillaway]

thanks so much for the info. we took a sample of our water to the pool supply place we go to and he is the one who told us to get the dry acid. he never mentioned muriatic acid, and we did tell him we had an above ground vinyl lined pool. Interesting. would you still recommend that we use the dry acid since we purchased it or should we get muriatic acid instead?

[chem geek]

You can go ahead and use it since you already have it, but when it runs out then the next time you need acid you can get Muriatic Acid from a hardware/big-box store. You can get the half-strength (15%-16%) version that fumes less. You can use The Pool Calculator to calculate dosages.