As opposed to flow-through filters, pressure filters route the pump pressure through the filter. They can also be used below the surface level of the water. Consequently they are used classically for higher positioned watercourses; they can be partially buried in the ground adjacent to the watercourse where they do not disturb the natural garden look. This makes the closed system of the filter possible, which is ensured by the quickrelease closure. Ideally inflow hose and outflow hose are routed through the pond liner with the Tradux system. The cleaning processes function in accordance with the same principle as that of the flow-through filter and consequently also offer, (with correctly matched pond and filter size), a good basis for optimally filtered water