The movement of water in an aquarium should be slow but steady. With regard to the filter flow rate, this means that the golden rule is as much as necessary, but as little as possible. In aquaria containing plenty of plants and only a small number of shrimps, the plants will produce enough oxygen for the animals in the aquarium. The less plants and the more animals there are in an aquarium, the more additional oxygen should be introduced via movement of the water surface.The flow rate through the Nano Corner Filter XLis infinitely adjustable. The filter outlet can be turned by 90. Despite a maximum pump delivery rate of 150 l/h, the filter is pleasantly quiet and energy-saving with a power consumption of only 2 W. The close-meshed intake openings ensure that the Nano Corner Filter XL is safe for shrimp and crayfish larvae. The filter has two filter elements. Advantage: When cleaning or replacing one filter element, the other filter element stays in the filter and is biologically active and ensures consistently high quality of the aquarium water. Also new are the nozzle pipe with an integrated cleaning valve and the attached mini-brush for easy cleaning of the nozzle openings. Cleaning the filter element is simplicity itself: Just grip the outflow pipe and pull the filter forward. The rear half of the filter housing remains in the aquarium. Wash the filter element in a clean bucket with aquarium water, to avoid harming the important filtering bacteria.