Feature:1. Hollow design, improve nitrification reaction, accelerate filtration, make water quality more healthy.2. Purifiy water quality, more conducive to the growth of organisms, suitable for seawater tank and other large fish tank.3. Stabilize PH value, add minerals, release trace elements, let fish grow more healthy.4. To accelerate the diffusion of nutrients in the filter material and promote the growth of nitrifying bacteria.5. Reduce the frequency of fish tank water changing to ensure the long-term health of water quality.6. Strong adsorption, a large number of micropores quickly absorb metal ions harmful substances, filtration effect is remarkable, is required for water purification filter materials.7. The bacteria culture ball can be used on both seawater and fresh water.8. Used for upper filtration, bottom filtration and outer filtration of fish tank.Specification:Condition: 100% Brand NewItem Type: Hollow Bacterium Cultivation BallMaterial: Sand StoneColor: As Pictures ShownPackage List:1 x Pack of Hollow Bacterium Cultivation Ball1 x Net BagNote:Put the hollow bacteria cultivation ball into the net bag, and then put in the filter device. It is recommended to clean it once every three months to achieve a cleaner filtration effect.