YEE Natural Volcanic Rock Aquarium Filter Media, 500G Fish Tank Filtering, Cultivating Nitrifying Bacteria | Removes Harmful Substances | Activated Water Health
The volcanic rock has low resistance to water flow, it does not cause blockage.
Allow culture of digestive bacteria (nitrifying bacteria)
Absorption of harmful bacteria, and heavy metals such as chromium and arsenic.
Stabilize the water pH value, and provides water filtration and water quality control.