I have used the 6 stage water general unit from ebay for years. It is a good unit. When you need resin or new cartridges though, get them from air water ice. Much better quality, and cheaper. I have 2 of the pressure tanks on my system, it makes for a quick refill of the water barrel. I use my system for tank water, the ice maker, and a faucet for RO water mounted on the sink.