Membrane selection comes down to feed water, not brand loyalty – salt rejection, flux, and fouling resistance all shift with TDS level, temperature, and whether the source is brackish or seawater. Toray Industries supplies the membrane material behind a large share of the industry’s brackish and seawater elements, and AMPAC’s membrane lines include Toray-built elements in the standard 2.5″, 4″, and 8″ sizes. AMPAC’s engineering team specs membranes off a feed water analysis first. Current stock: brackish water RO membranes and seawater RO membranes.