... : >200CSPECIFICATIONS TECH GRADE 6, Main content: 98.0 pct min7, P2O5: 58.0 pct min8, NaO: 25.0 pct max9, PH of 1% solution: 4.2 ... -4.8 10, Chloride, as CI: 0.003 pct max11, Water insoluble: 0 ... .1 pct max12, Heavy metal, As Pb: 0.001 pct max13, Arsenic, as AS 0.0003 pct max 14 ...