Hagen sponge filter cartridge U1 (MPN 010579) replacement for Fluval internal filters

Hagen sponge filter cartridge U1 is a replacement foam media engineered for compatible Fluval internal aquarium filters. The porous foam captures suspended particles and offers extensive surface area for nitrifying bacteria, supporting mechanical and biological filtration within small to medium aquaria. The cartridge is intended for routine maintenance and periodic replacement to help maintain water clarity and stable biological conditions.

Advantages

The open-cell structure of the sponge provides efficient debris retention while allowing water flow and oxygen exchange to sustain beneficial bacteria. It is dimensioned to fit specific internal filter housings, enabling straightforward cartridge swaps without modifying the existing filter assembly. The material is durable under normal aquarium conditions and can be rinsed to extend service life between replacements.

Suitable for

• Replacement of worn or clogged foam media in compatible Fluval internal filters
• Routine maintenance to restore mechanical filtration and biological surface area
• Small to medium freshwater and lightly stocked community aquariums

Key specifications

• Filter type: open-cell foam cartridge providing mechanical and biological filtration
• Compatibility: designed for use with matching model internal aquarium filters from Fluval
• Function: traps particulate waste and supplies surface area for beneficial bacteria colonization
• Material: resilient polyurethane foam suitable for aquatic environments
• Maintenance: washable to remove trapped debris; replace when degraded or permanently clogged

How to use

Turn off and unplug the filter before performing any maintenance. Remove the filter housing and take out the old sponge cartridge following the filter manufacturer’s access procedure. Rinse the replacement sponge gently in dechlorinated water or aquarium water to remove dust from packaging and to avoid killing beneficial bacteria. Insert the Hagen U1 sponge cartridge into the filter housing in the same orientation as the original part, reassemble the filter, and restart the unit. Observe water flow and check for leaks after reinstallation.

Usage recommendations

Rinse the sponge during regular maintenance using aquarium water rather than tap water to preserve bacterial colonies. Replace the cartridge when mechanical filtration declines, when the foam shows signs of wear or compression, or according to your regular maintenance schedule to maintain water clarity and biological balance.