The JBJ Ceramic Rings are the primary biological support for keeping toxic ammonia and nitrite at acceptable levels. in your reaction canister filter. Generally, the biological media should not be replaced unless detritus and waster is prohibiting the amount of exposed surface area available for the beneficial bacteria. Clean ceramic rings with the aquarium water and NEVER use tap water that can destroy the bacteria and cause you to have clouy water

Replace Ceramic Rings as needed or add extra for higher volume aquariums with large bio-loads.