Carefree Fish Aquarium Small Sponge Filter Air-Operated Quiet for 3~10Gal Fish Tank for Saltwater and Freshwater with 3Ft Tubing Biochemical Filtration Balls and Fluidized Beds(Not Include Air Pump). However, the most important function of the sponge is to prevent fish waste and other debris from entering the biochemical filtration chamber, which could affect the nitrifying bacteria system.
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