Classic Activated Carbons prime application is as a purifier and clarifier. It is a highly effective absorbent with a large internal surface area. Its vast porous structure allows it to catch unwanted contaminants from all aquaria. Its major treatment objective is the removal of dissolved organics as well as suspended solids and residual oxidants (chlorine and ozone). In addition, Classic Activated Carbon will aid in the removal of odor organics, micro pollutants and medications. Directions:For best results use ½ lb for every 50 gallons (189 liters) of aquarium water. Classic Activated Carbon has not been washed with chemicals, acids, or hydroxides. Therefore, it is necessary to thoroughly rinse with cold water. Following this rinsing process we recommend placing the carbon in a filter media bag. Place in high flow area of filter to maximize water flow through the media. For best results, replace carbon at least once per month. Classic Activated Carbon is ideal for use in all types of power filters, wet dry filters, canister or modular filters.