Abstract: A filter assembly for filtering a wide size range of impurities from a fluid. The filter assembly comprises a basket having a porous surface of a first average pore size defining an interior space for collecting impurities filtered from a fluid and a filter liner of a second average pore size less than the first average pore size disposed inside the basket for filtering impurities from the fluid. A nozzle is disposed at approximately a 20.degree. angle from the vertical axis for providing an unfiltered fluid to the filter assembly and for increasing the swirling intensity of the fluid therein. The present invention also contemplates a filtration unit including at least one filter assembly described above and a pump for suctioning an unfiltered fluid through the filter assembly so that the pump will draw a filtered fluid.