I really like my Purley H2O- Optima Chloramine advanced. I purchased it from
www.reefperfection.com (a canreef sponser). It has a few extra's that I really like. Dual inline digital TDS meter, built in TDS percent monitor that tells you when the RO is producing higher than normal TDS, auto shutoff with float, flush kit.
here is a link
http://www.reefperfection.com/purely...eadvanced.aspx