CHEMI-PURE brings the sea into your homeSoft corals - Crustose Coralline Algaes - Caulerpas - Gorgonias - Seafans - other invertebrates and fish of all species thrive and grow luxuriously with no water change necessary using real seawater or the better imported mixes. This is not a claim, but fact, experienced by thousands of CHEMI-PURE users. In fact, salt water fish have spawned repeatedly in 5 year old water. CHEMI-PURE does not remove trace elements and is the only filter medium which aids in the natural balance of positive and negative charges, with an emphasis on the beneficial negative ion. CHEMI-PURE comes packed in pure polyester filter bags in sealed plastic bottles, called 1 unit, one of which is recommended for up to 40 gallons of water, and which is completely active for 4-6 months with no 'regeneration' or cleaning required and is cheaper than carbon or pads.