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 isas 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 Dennerle Nano Corner Filter XL is 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 Dennerle 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 an