A filtration system using lightweight fibrous media (LFM) filter balls that are pre-compressed into an intermediary vessel or element before placing into an outer pressure-holding housing and where the LFM filter balls can be removed periodically to allow separation and relaxation of the media for cleaning. A plurality of lightweight fibrous media balls is pre-compressed at a predetermined ratio of compression and packing density inside their intermediary vessel or element before installation into an outer housing capable of holding pressures of a water flow, thereby forming a single filter mass providing multitudes of tortuous paths through which water can flow and the filter media can capture small particulate matter to reduce turbidity and other water-borne particulate contaminants.

A filter cartridge for an aquarium filter assembly includes a media pack and a frame supporting the media pack. The frame includes a non-clip fastener arrangement connecting the frame and the media pack.

A filter cartridge for an aquarium filter assembly includes a media pack and a frame supporting the media pack. The frame includes a non-clip fastener arrangement connecting the frame and the media pack.