The Dymax eZ Filter is an efficient and well performing internal filter that will help maintain proper aquarium health. Filter media within the filter have a high surface area, making it perfect for beneficial bacteria to colonize and thrive. The eZ Filter has all its media separated with a filter basket and includes white wool (mechanical filtration), activated carbon (chemical filtration), and biological sponge (biological filter). Filter media should be cleaned or replaced regularly to maintain optimum performance. The Dymax eZ Filter is powered by a powerful Dymax pump. It will draw water from both the top and bottom levels of the water column, and water will be expelled towards the middle. This internal filter is suitable for both freshwater and marine aquariums. The Dymax IQ Skimmer can be attached onto the Dymax eZ Filter for marine aquariums so that protein skimming and filtering can all be done by one unit. MODEL EF-20 EF-30 EF-40 OUTPUT 500 L/H 600 L/H 600 L/H POWER 15W 15W 15W HMAX (M) 1.0M 1.2M 1.2M DIMENSIONS (IN) 3 x 6 x 8 3.25 x 6.25 x 11.5 3 x 6.25 x 15 TANK SIZE Up to 27 gallons Up to 40 gallons Up to 53 gallons