Citric acid for pool rust stains

Citric acid for pool rust stains.

Yes, it works and it’s safe for concrete pool surfaces. No need for harsh muriatic acid if the stain isn’t thick.

Mix citric acid powder (food grade is fine) with a little water to make a paste. Scrub it into the rust stain with a stiff brush. Let it sit for 10–15 minutes, then rinse with a hose. If the stain is stubborn, repeat.

The key safety point: citric acid is mild enough that it won’t eat your concrete or throw your pool chemistry into chaos like muriatic acid can. Just don’t let the paste dry out completely, and rinse thoroughly before anyone swims.

Better than messing with strong acids for most stains.