In my RO the membrane is a TFC meaning(Thin Film Composite)is best used on chlorinated water systems.My DI is a multi-layered-mixed bed deionization cartridge.This cartridge removes almost all minerals and organics that may pass through the membrane,producing laboratory grade water.As far as brands go ther are many.I have had good luck with my Spectrapure CSP/DI 60GPD unit.Customer service has been great.
