A medium having a support structure configured for circulation of a fluid therein,
such as a replaceable filter cartridge, including a sanitizing agent which contains
one or more reactants that are chemically configured for delivering chlorine dioxide
or other sanitizing agents in a controlled dose to sanitize, deodorize, and disinfect
upon being wetted by the fluid and positioned in the medium support structure to
be exposed to the fluid circulating therein.
