... solution 9.2-10.0 2. Food grade Main content, %: 94.0 P2O5%; 57.0 Water insoluble %; 0.05 Iron, as Fe %; 0.01 pH of ... 1% water solution 9.5-10.0 Heavy metal, as Pb %; 0 ... .001 Arsenic, as As, %; 0.0003 Fluoride, as F, %; 0.003 Chloride, as Cl ...