Deionization RO System Filter SetOur combination of Reverse Osmosis and Deionization creates the ideal home system for the purest water possible. In systems that only use Deionization (1 stage), resin mixed bed ion exchange creates water just as pure but you will constantly be replacing your Deionization filters and media. The four stages of filtration before the Deionization dramatically increase the lifespan of your Deionization filter, giving you a much lower lifetime cost than