... Treatment Chemicals. Amino Trimethylene Phosphonic Acid (ATMP)2-Phosphonobutane -1,2,4-Tricarboxylic Acid(PBTCA)CAS No. 37971 ... itemsindexAppearanceColorless or light yellow transparent liquidActive acid %49.0-51.0Phosphorous acid(as PO33-)%0.8 ... TRICARBOXYLIC ACID;2-Phosphonobutane -1,2,4-Tricarboxylic Acid;2-Phosphonobutane-1,2,4-tricarboxylic acid PBTC; 2-Phosphonobutane -1,2,4-Tricarboxylic Acid ...