For better filtration, we recommend filling your filter housing with biological media. The addition of biological filter media will create a more suitable habitation for beneficial bacteria to grow, enriching your aquarium and keeping a more reliable and balanced ecosystem. An appropriate biological filter media that we suggest is the Bio Filter Media by Sera which can be placed directly into your filter housing.
For the replacement of your carbon filter cartridges, we recommend using Nylon Filter Bags by Ocean Five in combination with our ROX 0.8 Activated Carbon. The Nylon Filter Bags are also suitable for keeping other smaller filter media contained in your filter housing.
Filtering Foam should not need to be replaced with proper maintenance.