Designed for koi ponds over 6,000 gallons, the Twister Settling Chamber provides excellent mechanical filtration in an easy-to-clean unit. The 12 sided design allows for multiple outlets where it is convient for your application. This Vortex filter can easily be added to any established pond with little work. The 4" output allows for no restriction or backflow in the filter. This Settling Chamber works best as a Gravity Fed System, however, can also be a Combination System. As a bonus, the Hurricane Settling Chamber can be customized to fit your needs with additional 3" or 4" inputs. Unlike plastic cones, the Hurricane series of filters are constructed of heavy-duty fiberglass and will not warp or distort. Every system is made in the USA and features our exclusive Lifetime Filter Body Guarantee.