... 85%, Phase I 5-40, Fe max 70PPM Sodium Tripolyphosphate (STPP)Synonyms: triphosphoric acid pentasodium salt, pentasodium triphosphate, tripolyphosphate pentasodium, sodium ... triphosphate, STPP, armofos, empiphos stp-D, freez-gard FP 19, polygon, rhodiaphos ...