A unique composition which easily and effectively removes hard water scale, lime deposits, iron scale and rust from metals, glass, ceramics, fiberglass, rubber and plastics without marring or discoloring surfaces. Effective on evaporative coolers, cooling towers, air washers, water distillation units, heat exchangers, boiler/steam generating equipment, coils, pipes, fittings, and water fountains. Not recommended for use on colored grout or natural stones, unless properly sealed. Available in 1 gallon (4 in a case), 5-gallon pail or 55-gallon drum.