Abstract: Apparatus for improving the efficiency of swimming pool skimmers in cleaning the surface of water in swimming pools of particulate debris are disclosed. The apparatus of this invention includes a mounting bracket adapted to be permanently installed at the wall of a swimming pool, in one embodiment at the intake aperture of a swimming pool skimmer, and having therein a slot configured to receive therein an elongate prismatical member. The slot is so configured that when the prismatical member is inserted therein, the prismatical member is held rigidly in the water of the swimming pool at an angle to the wall of the swimming pool and a depth in the water of the swimming pool to substantially increase the rate of capture of the water surface debris by the skimmer. The prismatical member has a height dimension selected to prevent debris from either splashing over the top thereof, or tunneling through laminar flow paths beneath the prismatical member.