The ACM1 offers the highest rejection (99.5%) and typically operate at 150 - 200 psi (10 - 14 bar). The ACM1 is preferred in applications with high feedwater TDS (>3,000 ppm) and/or high recovery. The lower specific flux of this membrane compared to the ACM4 and ACM5 allows for a more balanced hydraulic flow through the system and more balanced permeate flux rates due to the high osmotic pressure of these feedwaters.