100pcs 18mm Biological Bio Balls Aquarium Fish Nano Tank Wet/Dry Canister Filter Media Black

Features:Great for fish tanks, to promote gas exchange and increase dissolved oxygen levels.Great for tropical fish farms, koi ponds, waste water systems, etc.For use with wet/dry filters (here is not included), to improve biological filtration.Aiding in the critical gas-exchange process that is needed for successful biological filtration. Discounted at only: US$ 5.98