Eheim's Fine White Filter Pad is used as the last stage of filtration, to polish water of very fine particles before it is returned to the aquarium. Once it has become soiled, it should be replaced to avoid damage to the motor head of the filter.
Eheim's Fine Filter Pads are a critical final step of the 2217 Canister Filter system. Eheim's fine filter pads polish your tank water and remove any remaining small particles from debris and waste. Clean, clear water is returned to your tank in no time.
Filter longevity depends on tank activity. It is recommended that the filter be changed once it appears soiled. Tanks with higher fish loads or multiple turtles, for example, may need a filter change more often that you may think.