Suitable? One that is very popular in environmental labs is the Millipore Milli-Q system. http://www.millipore.com/catalogue/module/c7658. It's very compact. But it is slow - about a gallon in 10 minutes or so if I remember right. But that's fine for a small lab. About $2000+ or so depending on model. http://www.aibltd.com/listings.cfm?show=1&catid=302 Several on ebay right now