Pool Season pH Down, 2.5 lb Bottle, 47251440

Pool Season pH Down is a granular dry acid in a 2.5 lb bottle, made up of 93.2 percent sodium bisulfate. It lowers the pH of pool water slowly and effectively.

Why pH matters

pH sets how well everything else in the pool works. When it drifts high, chlorine becomes far less effective at the same measured level, so the water tests fine on paper and still goes dull or green. High pH also pushes minerals out of solution, which is how scale gets onto plaster, heater tubes and filter elements.

Dry acid versus liquid

Sodium bisulfate does the same job as a liquid acid without the fumes, the splash risk and the awkward jug. It is the product of choice for lowering pH on most residential pools for exactly that reason.

Using it

Add in stages against the dose on the label rather than all at once, run the pump to circulate, and retest before you add more. It is far easier to take pH down in steps than to bring it back up after overshooting.