Dow Filmtec XLE-4040 Extra Low Energy Commercial RO Membrane New Dow Filmtec XLE elements offer better system performance and economics by operating at a very low applied pressure Dow Filmtec membranes are available in a variety of sizes to meet a range of space requirements May be cleaned over a wide range of pH levels (pH 1-13) for maximum cleaning effectiveness Maximum Pressure Drop: 13 psig Free Chlorine Tolerance: &lt;0.1 ppm