They are a very low end drinking water quality system is all and in no way reef quality. You get what you pay for with RO/DI and a reef system is going to run you bwetween $170 and $250 for anything worth its weight.
Take a look at the BFS-161 75 GPD Premium found here for $169
www.buckeyefieldsupply.com . It includes a 1 micron prefilter, 0.5 micron 20,000 gallon carbon block, 75 GPD Dow Filmtec RO membrane, full size vertical 20 oz refilable DI, capillary tube flow restrictor, TDS meter, Pressure gauge, thermometer, DI bypas valve and more.
Reef quality systems always have a 1 micron or lower prefilter, should use a 1 micron or lower carbon block, use full size 10" vertical refillable DI filters and the better ones include TDS meters, pressure gauges and capillary tube flow restrictors. You NEVER want a granular carbon filter, it grinds to dust and fouls the membrane besides adding TDS back to the water. Horizontal DI's are next to useless so good vendors don't use them. They short circuit or channel so provide poor treatment even if you stack two or three together they stiil do not work nearly as well as a single full size 20 oz 10" vertical that fills from the bottom up so all water and resin come into contact with each other.
Other suggested vendors are
SpectraPure Water Purification Products ,
FL Aquarium Water Filters Reverse Osmosis Booster Pump GFO Nitrate DI Carbon ,
Melevsreef.com - Welcome! and even
Bulk Aquarium Supplies - Reef Aquarium Supplies | BulkReefSupply.com .