Abstract: The present invention is directed generally toward a modular apparatus for the circulation, filtration, and chlorination of water in an in-ground swimming pool. In more particular, the invention disclosed herein relates to a modular and transportable pool-side unit in which the entire filtration and circulation systems, as well as the lighting and chlorination systems, for the pool are contained. Additionally, the instant invention utilizes a novel traveling main drain, wherein the functions of a conventional pool main drain and an automated pool sweeper are combined. The traveling main drain is moved about the bottom of the pool by the expulsion of water through a single horizontally mounted jet, said jet being free to rotate in a horizontal plane about the central axis of the device and thereby seek another movement direction when the device becomes blocked.