External Hang-On Filter Hagen Fluval U2 for 45–110 L Aquariums, 5 W, Fresh & Saltwater

Hagen Fluval U2 is an external hang-on filter engineered for aquariums with a capacity of 45–110 litres. The compact unit (90 × 200 × 100 mm) is designed for both freshwater and marine environments and delivers three-stage filtration — mechanical, chemical and biological — to support stable daily water quality. With a rated power consumption of 5 W and wide AC input compatibility (120–240 V, 50/60 Hz), the Fluval U2 provides efficient filtration while maintaining low energy use and a small footprint suitable for small to medium tanks.

Advantages

The Fluval U2 combines three-stage filtration media to remove particles, absorb contaminants and promote beneficial bacterial colonisation. Its hang-on design increases circulation and surface agitation to improve oxygen exchange and overall tank health. Compact dimensions and quiet operation allow flexible placement on a variety of aquarium setups. Energy-efficient motor operation minimises running costs while delivering consistent flow and reliable performance for routine maintenance.

Suitable for

• Community freshwater aquariums 45–110 L
• Small marine or reef-start aquariums within the specified volume range
• Planted tanks where gentle but effective circulation is required
• Quarantine or hospital tanks needing reliable filtration and aeration

Key specifications

• Recommended tank volume: 45–110 litres
• Power consumption: 5 W
• Electrical input range: 120–240 V, 50/60 Hz
• Filtration stages: mechanical, chemical, biological
• Device dimensions: 90 × 200 × 100 mm
• Mounting type: external hang-on
• Suitable for: freshwater and saltwater aquariums

How to use

Mount the filter on the back rim of the aquarium ensuring the intake sits at the proper level for optimal flow. Prime the unit and install the provided filter media in the correct order to ensure mechanical, chemical and biological filtration. Connect to an appropriate power source within the specified voltage range and verify smooth, quiet operation and steady outflow across the tank. Monitor flow rate and check media condition regularly; replace or clean mechanical media when visibly clogged and renew chemical media according to manufacturer guidance to maintain water quality.

Usage recommendations

For best results, pair the Fluval U2 with regular partial water changes and routine maintenance. Inspect impeller and intake monthly for debris, and avoid placing the unit where splashing or unstable mounting could interrupt flow. When used in marine aquariums, monitor salinity and protein skimming separately to ensure stable conditions alongside the filter’s three-stage filtration.