Specifically designed for the Fluval U4 filter, the U4 Poly-Max Cartridge helps control green water and unsightly algae growth by trapping and adsorbing phosphate, nitrite and nitrate.

Key features:

• Chemical filter media
• Produces crystal clear water, reduces odour, and creates ideal conditions for fish and plants
• Helps reduce overall aquarium maintenance
• Suitable for freshwater, saltwater or reptile environments
• Convenient 2-pack format - 2 x poly/clearmax filter cartridge