Specifications: C6H8O7.H2O: 99.5-101.0% Heavy Metals: 10 ppm max Calcium: 200 ppm max Iron: 50 ppm max Chlorine: 50 ppm max Oxalates: 350 ppm max Sulphates: 150 ppm max Sulphated Ash: 0.1% max Moisture: 7.5-9.0%