Pure Aqua, Inc. designs and manufactures water treatment systems in addition to double pass reverse osmosis. In November 2013, the double pass reverse osmosis was delivered to a major company in Yemen. The system came complete with pretreatment consisting of a multimedia filter, carbon filter, and a water softener. The double pass system was designed to produce 1,200 GPD at a maximum 640 PPM feed water TDS from which the product will feed another pass RO system with will produce 600 GPD . For more information click here: http://www.pureaqua.com/commercial-reverse-osmosis-systems-ro-200-series.html