... Supply Direct 3.Crystals Powde Sodium Hexametaphosphate,SHMP 68% (Tech Grade) Synonyms: Hexasodium metaphosphate, Graham's salt, Glassy sodium, Sodium Tetrapolyphosphate, hexametaphosphate sodium salt, Metaphosphoric acid hexadosium ... P2 O 5 )% ≤ 7.5Iron (Fe) % ≤ 0.05PH Value 5.8-6.5Solubility passWater Insoluble matter % ≤ 0.05Polymerization 9-21Fineness (mesh ...