Magnesium sulfate heptahydrate EPR, 500 g

Assay 98.5% pH (5% water)

5.0 Substances insoluble in water (H2O) 0.01% Chloride (Cl) 0.0035% Phosphate (PO4) 0.005% Heavy metals (Pb) 0.0005% Arsenic (As) 0.0002% Calcium (Ca) 0.05% Iron (Fe) 0.002%