In addition to the filter media fitted at the factory, JUWEL Aquarium offers a range of additional filter media. 2. If your aquarium shows increased ammonium values, you should used our filter medium “Amorax”. It quickly and effectively binds ammonium, prevents the formation of ammonia and promotes the vitality of your fish. 3. If you perceive odour formation in your aquarium, or if the water changes in colour, you should use the filter medium “Carbax”. 4. The filter medium “Cirax” provides an even greater surface for filter bacteria to settle, than the fine filter sponge bioPlus, and it thus provides for a consistent filtering effect in your aquarium. 5. If your aquarium shows increased phosphate values, you should use our filter medium “Phorax”. This medium removes phosphates from your aquarium, and it effectively reduces algae growth and promotes improved plant growth.