Tetra Whisper Power Filter for Aquariums, 30-60 Gallon Product Features QUIET & RELIABLE: The Tetra Whisper Power Filter uses 3-stage filtration to create clear, clean water. PF 30-60 treats aquariums up to 60 gallons. CATCHES DEBRIS: Dense, dual-sided mesh filters debris and fish waste. CARTRIDGE REFILLS: Change cartridges monthly; uses large-sized Tetra Whisper Bio-Bag Cartridges (refills sold separately). INNOVATIVE CLEANING POWER: Integrated Stay Clean technology reduces buildup on glass and binds small dirt particles to make them easier to filter. ABSORBS ODORS: Ultra-Activated carbon removes both odor and water discoloration.