I found a local person but I don't think his units have the GAC, assuming I should get one with that. He emailed me this info below.
Here's what you'll get, first of all my unit are custom built one at a time, installations free.
stage one: 1 Um sediment filter - upgradeable to a .5 Um ceramic sediment filter (add S$20)
stage two: Kemflo~T33 OCB GAC coconut carbon filter
stage three: the work horse (matrix CTO Carbon Block ~ KX) the best filter on the market
stage four: you can either have a 100 or a 75GPD membrane - Dow Filmtec (100GPD has a rejection rate of 90%* 75GPD has a rejection rate of 99.6%)
stage five: nuclear grade mixed DI resin Posted via Mobile Device