Carbon filter element 10”, used in the 10” blue filter housings for the Fresh Water Flush (for Aqua Series manufactured after 2008) and the blue Charcoal after treatment filter housings. Removes foul odors from the Product Water. Sulfurous odor (i.e. “rotten egg smell”) is caused when biological matter dies and decays in the Feed Water section. Flushing the System with fresh water helps to minimize this odor