They are built into the side wall of the basin and connected to the suction pipe of the filter pump. Inside the large volume, stainless steel skimmer housing is a suction port, masking frame and dirt strainer basket with a floating flap. Masking frame, dirt strainer basket with floating flap form a compact unit. For discharge of collected dirt particles this unit can be easily taken out from the front side. The floating flap is moving and adapts to the varying water level. It is provided to break the tension of water surface and increase the suction velocity of the skimmer inlet. Due to the increased suction velocity the floating dirt is sucked into the strainer basket more efficiently and stored inside for discharge. The skimmer housing has got a suction port from beneath.