The ProfiClear Premium drain module L is the ideal final module in the ProfiClear Premium filter system. It provides the finishing touch in terms of clear water. The already mechanically filtered water passes through a large bio-filter stage in the ProfiClear Premium L drain module. It is connected to the preceding OASE ProfiClear Premium Standing Bed Module L fixed bed filter via two inlets. Five integrated ClearWave filter elements now ensure optimum water clarity in the drainage module L. By optionally enriching the water in the drain module L with air (this is done using bubble stones), the water movement in the tank is optimised, including the colonisation of the filter elements with bacteria. Finally, the water is returned to the pond via the outlets, sparkling clean.