Dow Filmtec TW30 High Rejection Reverse Osmosis Membrane This membrane is rated from (75-600) Gallons per Day. If you have chlorinated water, we recommend you use a Carbon/Sediment Pre Filter. The residual chlorine in municipal or city water will destroy the Thin Film Composite (TFC) membrane. Dow Filmtec TW30 Reverse Osmosis Membrane elements are for home drinking water. The industry's most reliable advanced membrane technology and automated fabrication, allow these elements to deliver consistent performance that equipment suppliers, water treatment dealers and residential customers can rely on. The industry's most reliable for home drinking water is the Filmtec reverse osmosis membrane elements. Advanced membrane technology and automated fabrication in the Filmtec reverse osmosis membrane allow these elements to deliver consistent performance for all customers. Filmtec reverse osmosis membrane TW30 element is NSF/ANSI Standard 58 listed. Filmtec home drinking water elements are rated at 50 psi and will purify about 20% more water than competitive elements rated at 60 psi. Because of environmental factors actual production may vary