RO & Dow Membranes

AMPAC stocks thin-film composite membrane elements — including Dow membranes — for brackish water and seawater desalination systems, covering residential, commercial, and industrial reverse osmosis elements in a range of sizes and rejection rates. Many of these come from Dow Chemical Company’s FILMTEC line, valued for steady water production and high flow rates.

Residential units come in 50, 75, and 100 GPD output ratings. Commercial and industrial elements span 300 to 3,500 GPD per element, with rejection rates from 96% to 99.7% TDS depending on the application.

Thin film composite membrane construction sits at the core of modern reverse osmosis. A thin polyamide layer bonded to a support material blocks dissolved solids while letting purified water pass through. That’s how source water — well water, municipal tap water, or seawater — becomes clean product water. This advanced membrane technology lets a small residential unit under a sink do the same basic job as a large industrial plant, just at a different scale.

Plan on replacing your RO membrane every 2-5 years. Feed water TDS, temperature, and daily production volume all affect service life. A spent element shows itself through rising TDS in the product water, reduced flow rate, and increasing pressure differential across the housing. AMPAC carries these elements sized to fit most major residential and commercial RO housings, so swapping in a new one is usually a drop-in replacement.