A liner for use with a basin to contain a liquid features two bodies of flexible plastic which are joined at adjacent faces of the distinct plastic bodies so as to form an interface of the plastic bodies. The liner includes an air conduit adapted for guiding pressurized air substantially within the thickness of the bag from an air discharge apparatus, which generates the pressurized air, to the interior of the liner. A length of the air conduit is formed at the interface of the plastic bodies such that a circumferential wall of the length of the air conduit is defined in part by an inner face of each plastic body. The plastic body of the liner that is arranged to contact an inside face of the basin is substantially imperforate so as to isolate the liner interior, where the liquid is received, from the basin.