OA-50 Oxalic Acid Powder Concrete Brightener and Rust Remover

Remove hard water, scale and rust stains from concrete, tile and grout. Perfect for pools, showers, patios, and sidewalks. Sold as a powder, so you can make it strong enough for any job. One 50 pound box of Powder can make up to 400 gallons of powerful cleaner.

Mixing: Mix 1 to 8 ounces per gallon of water to make a liquid concentrate. Dilute the concentrate as necessary.