What to do if you want to ventilate your tank better allowing to bring more air into the water for your fishes? Easy either buy an additional costly air pump with some equipment or attach a diffusor to your current waterpump. If you deside to choose the second method print it attach it done. The diffusor is available in different sizes. the number at the end of the filenmae describes the inside diameter of your hose in milimeters. Make sure that the air hose you attach is not submerged otherwise you can't pull air into the aquarium. The connection for the air hose is allways designed for a hose with 4mm inside diameter.Make sure you print with supports otherwise the air hose connector can not be printed.