Innovative backwash system for sucked-in waste auto- removal, easy to operate Patented design of viewable pressure-alarm indicator for timely reminding of backwash cleaning and maintenance Multi-layer of mechanical and biological filtration system containing bio-balls and three layers of filter sponge for removing harmful debris and breeding beneficial bacterid Optional version with integrated UV clarifier with superior shatterproof quartz sleeve brings great filtration performance Model EPF13500 Qmax 18000L/H Applicable Volume 18000~36000L Dimensions: 45.5*42.5*65 cm