A strong hydrochloric acid (previously called muriatic acid) cleaner & deoxidizer for removing alkali scale and mineral deposits from swimming pools, drinking fountains, water cooling towers, water meters and cooling coils. To clean excess mortar from building exteriors and to etch old concrete floors before applying seal coatings. Use with caution. Read label and M.S.D.S. precautions. USDA (A-3), 36% HCI. pH full strength <,5; 1 to 1 = , .5.