Patent ID: 7468134

Claim:
In a pond filtering and cleaning apparatus having a filter tank, a multi-port valve, a strainer, a diffuser head, and biological filter media, an improvement comprising: hollow tubular biological filter media having a plurality of outside longitudinal ridges and and a plurality of valleys extending therebetween, each valley is substantially u-shaped and facilitates preventing interlocking of said filter media; and a plurality of internal free-standing fins comprising a first end, a second end and a body extending therebetween, each fin is coupled to said filter media using said first end and extends radially inward from a tubular portion of said filter media towards a center axis of said filter media such that said second end is positioned at a distance from the center axis of said filter media; a diffuser head having a substantially cylindrical outside wall that comprises a plurality of substantially vertical slots defined therein, wherein each slot is substantially parallel to a center axis of said diffuser head and oriented at an angle measured with respect to a plane substantially tangent to said outside wall, said slots being spaced evenly around the circumference of said diffuser head and extending slightly into a tapered upper surface of said diffuser head, wherein said plurality of slots are sized to facilitate providing sufficient water pressure to enable an upward spiral movement of water during backwash mode and an unrestricted water flow during a filtering mode.