Hydra-Home Unit Internal Filter ReplacementActivated carbon is a porous element that traps compounds, present in a gas or liquid. It does this so effectively that it is the most widely used purifying agent used in water filtration. In general, carbon filters remove at least 81 chemicals and are effective at reducing another 52. According to the EPA, activated carbon is the ONLY filtering material that removes all 12 identified herbicides and 14 pesticides, along with all 32 identified organic