Building on the mighty FX performance and reliability platform, the all-new FX4 high performance canister filter is a compact 'little brother' to the FX6. The FX4 bridges the gap between the Fluval 406 and the FX6 canister filter, making it an ideal choice for aquariums up to 250 US Gal (1000 L). - Multi-stage filter pumps out 2650 L of water per hour - Smart Pump advanced microchip technology continuously monitors and optimizes pump performance - Self-starting just add water, plug in and Smart Pump will take over. - Trapped air auto-evacuated every 12 hours to ensure maximum efficiency - Easy water changes eliminate need to lift heavy buckets. Simply attach hosing to output and Smart Pump does the rest - Removable, stackable media baskets eliminate water bypass and hold a - An ideal choice for aquariums up to 1000 L.