Assay (C2H3NaO2); Dried Basis) 99.0-101.0% PH of a 5% solution 7.5-8.5 MAXIMUM LIMITS Calcium (Ca) 0.005% Chloride (Cl) 0.002% Heavy metals (as Pb) 0.001% Insoluble matter 0.01% Iron (Fe) 0.001% Loss on drying 1.0% Magnesium (Mg) 0.002% Phosphate (PO4) 0.001% Sulfate (SO4) 0.003%. 25kg per bag.