Boyd Enterprises Chemi-Pure is an ionic media acts mechanically as well as chemically, absorbing all the various elements of decomposition. The resin produces negatively charged ions, while removing excess acids and ammonia.
Keeps pH at constant level
Chemical absorption filter
Aids in the natural balance of positive and negative charges
Chemi-Pure comes packed in pure polyester filter bags in sealed plastic bottles.  A 1/2 unit, treats up to 20 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. Use 1 1/2 unit up to 20 gallons and above 20 gallons use full unit or equivalent in half units. 
Please note: product is supposed to arrive moist. (As carbon draws moisture from the resin beads in this product, once they crack or dry, they are no longer active, so it must be shipped and used while moist).