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 Dennerle Nano corner filter XXL is a high-performance device with a pump delivery rate of 390 l/h. The pump runs so smoothly and quietly that it is practically inaudible. Its modest power consumption of just 5,1 W additionally helps to conserve natural resources. The water flow rate is infinitely adjustable and the filter outlet can be rotated by 90to enable the flow of water to be channelled in any desired direction. The filter incorporates a nozzle tube with integrated cleaning slide and a mini-brush for simp