CHO Concrete CleanerA citric acid based cleaner required for washing substrate prior to staining with Elements Transparent Concrete Stain. Opens the pores of the concrete surface to ensure proper penetration. Extremely effective for removing efflorescence and other organic stains from the surface of concrete. Packaged in 1 pound (0. 5 kg) and 5 pound (2. 3 kg) units, the concentrated powder must be mixed with water prior to use. Can be used to aid in removal of release