Replacement Bio-Foam Sponge Insert for Fluval FX5/FX6 External Filters (FV-2391)

Replacement Bio-Foam Sponge Insert for Fluval FX5/FX6 External Filters (FV-2391) is a shaped foam media pack made to fit the media baskets of Fluval FX5 and FX6 canister filters. The foam provides mechanical filtration by capturing suspended particles and biological filtration by offering a porous surface for beneficial nitrifying bacteria to colonize. This insert is intended for routine maintenance and media refresh to help maintain water clarity and biological stability in both freshwater and saltwater aquaria.

Advantages

The foam insert combines debris-trapping mechanical filtration with high-surface-area porosity for bacterial colonization, supporting effective ammonia and nitrite processing. Its shape and dimensions match Fluval FX5/FX6 media baskets for straightforward replacement and secure fit. The open-cell structure resists clogging when rinsed properly, and the material is compatible with repeated cleaning cycles during regular maintenance.

Suitable for

• Home freshwater aquariums using Fluval FX5 or FX6 external filters
• Marine and reef tanks where mechanical and biological filtration is required
• Routine filter maintenance and media replacement to restore flow and filtration efficiency
• Hobbyists needing spare or replacement media inserts for canister filter upkeep

Key specifications

• Function: mechanical and biological filtration
• Material: open-cell foam designed for aquarium use
• Compatibility: shaped to fit the media baskets of Fluval FX5 and FX6 canister filters
• Maintenance: washable and reusable when rinsed in aquarium water
• Intended use: freshwater and saltwater aquaria

How to use

Shut off and disconnect the filter according to the manufacturer’s safety instructions. Open the canister and remove existing media baskets. Replace the old foam insert with this replacement Bio-Foam, ensuring it seats properly in the designated media basket. Reassemble the canister, reconnect hoses, and restart the filter. Rinse the new foam gently in aquarium water if required to remove any loose particles before installation. Follow a staggered replacement approach if preserving established biological filtration is a priority.

Usage recommendations

For best results, inspect the foam during regular maintenance intervals and clean by rinsing in dechlorinated aquarium water to avoid killing beneficial bacteria. Replace foam inserts as part of a planned media refresh cycle rather than all at once to maintain biological stability. Monitor flow rate and water parameters after installation to confirm proper performance.