Replacement filter pad set for Betta UV Canister filter. Includes 2 x Fine White filter pads and 1 x Coarse Blue filter pad. It is advisable that you clean the filter in old aquarium water during maintenance. Do NOT clean the filter in tap water as chlorine and chloramines will remove the beneficial nitrifying bacteria that have colonised during the maturation of the aquarium. Replace as and when required (heavy wear, constant blocking).