A device for filtering fluid includes a hollow housing (10) having a fluid inlet (26) and a fluid outlet (28). A filter element (50) formed of fluid permeable material is disposed within the housing (10) for filtering fluid entering the fluid inlet (26), the fluid passing through the element (50) and out the fluid outlet (28). The element has a generally cylindrical configuration with the permeable material forming a plurality of elongated, radially extending pleats (98). The pleats are supported by spacers (81) having a plurality of blades (102) attached to a web (106) with channels (104) therebetween. The element (50) is used as a septum for supporting a diatomaceous earth precoat. A regeneration piston (76) creates fluid flows within the filter that cause the element (50) to flutter, thereby displacing the diatomaceous earth precoat from the septum for regeneration.