SellBeijing KaiBiYuan-Selling volc

Volanic poriness：the inside and outside average poriness is about 40%, the resistance to water is very small, comparing with the same kind filter, it costs less, but can reach the expected filtering purpose. 2、The specific surface area: the specific surface area is large, the opening holes are many and inertia, so it is suitable for microorganism to touch and form film, keeping large quantity of microorganisms, so it is favorable for the transference of the oxide and nutrition, and waste during the metabolism. The filter shape and water flow regim: Since volcanic biological filter is granulous