Fluval FX4High Performance Aquarium Canister Filter Multi-stage filter pumps out 700 US Gal (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 total of 1 US Gal (3.9 L) of media Compact 41.9 cm (16.5 in) tall design - easily fits under most aquariums All filter media included - mechanical, chemical and biological