MBBR media

Dier Chemical 's Bio carrier(Bio medias ,MBBR media) :

With technology from sewage purification plant and this medium has been developed to have a very large surface which can rapidly form a biofilm with good bacteria. The other big advantage is that they float and mixed with air, they will constantly be kept in motion, and thus cleared of killing bacteria and never clog with dirt. 
When the medium is first put in the water, it may seem very viscous and difficult to get moving on. After a few days to a week so the medium has matured and will have a position just below the water surface.

Nomal size :  Φ12×7mm, Φ11×7mm, Φ10×7mm, Φ14.5×9.8mm,  Φ25×12mm.