Fluval 306/406 & 307/407 Nitrite Remover. Designed specifically for the Fluval 07 performance canister filter series, Nitrite Resin infused Pads perform double duty as both an effective mechanical and chemical media. Key Features : Specifically designed for Fluval 306/307 & 406/407 filters Effective at removing and reducing nitrite Effectively traps floating particles for clear water (debris, excess food, and waste) Supports beneficial bacteria for a healthier aquatic environment Custom fit to increase filtration efficiency For best results, replace monthly or as required after testing water with your Fluval test kit Convenient 6-pack format For use in freshwater and saltwater aquariums.