fluid flows serially through the cartridges to outlet 116 where the final purified product is delivered as shown the outlet 116 is a male type outlet which together with the inlet port may be adapted to couple with the purification console not shown the various connectors may be modified as apparent to those skilled in the art for example the male and female type ports may be interchanged or other type ports may be provided additionally o rings may be provided in an annular groove on the male connection to form a seal in addition to reducing the likelihood of fluidizing the filter media the downward flow also reduces the possibility that flow channels may form through the media channels form when the filter media has a vein or channel of decreased density that provides a path of least resistance through which fluid will flow the formation of channels can substantially reduce the effectiveness of the filter media because the surface contact between the media and the water is reduced the direct connection between the outlet of one cartridge to the inlet of another also minimizes the length of conduit through which the filtered fluid flows and thus decreases the likelihood of contaminating the fluid with impurities in the conduit finally another advantage of the inventive filter cartridge assembly is that each cartridge unit 92 94 96 and 98 can be replaced individually without destroying or affecting the other cartridges since each cartridge unit may contain one or several different filter media the service life time for each cartridge unit may be different because each cartridge assembly is constructed of a plurality of self contained cartridge.