Aqua Mix Phosphoric Acid Cleaner Substitute Aqua Mix Phosphoric Acid Cleaner Substitute is a designed to eliminate tough stains Removes grout haze, rust, lime, hard water stains, deposits, efflorescence, and soap scum Concentrated acid formula is ideal for a variety of acid-resistant natural stone surfaces Use with granite, slate, travertine, ceramic, porcelain, Saltillo, cement, and masonry