Forced Filter Box: The biochemical cotton aded with activated carbon which in inner layer has th effect of separating the lage particles of impurities, and can remove some harmful substances such as ammonia, peculiar smell. The materials of out layer of this component is high-density cotton, and it: Is equipped with the oil firm collector. Adopts the mute design and it is reliable. Adopts the scalable design of prolonging inlet pipe. Is easy to install & maintain. Suitable for tank ≤ 35cm.