Sodium bisulfate

Sodium bisulfate is a granular option that many owners find safer to store and carry than liquid acid. It still burns skin and eyes, so wear gloves and eye protection and follow the label.

It works like muriatic acid but is milder. It lowers pH and alkalinity, and it can add sulfates over time. Add it in small doses with the pump on, then retest after a few hours before adding more. Keep it dry and away from chlorine products. Dust and fumes irritate the lungs, so do not pour it indoors.