Disclosed are systems and methods for sealing components in a spa shell. A through-component body, such as a spa jet, extends from the inner side of the spa shell to an outer side of the spa shell. A retaining member includes at least one injection port, and retains the through-component body in place on the outer side of the spa shell. A sealant is injected into the at least one injection port to seal a space between the outer side of the spa shell and the through-component body.

A bathwater circulating system has a pump operable to draw fluid in at an intake port and expel it under pressure at an output port. Water- and air-supply conduits feed water and air to the intake port at a rate determined by a flow-restricting air-intake valve so that the pump mixes the water and the air, pressurizes the mixture and thereby dissolves the air in the water, and expels the air/water mixture at the output port. A pressure-reducing valve is connected by an output conduit that extends from the output port to the pressure relief valve and conducts the water/air-bubble mixture from the pump to the pressure-reducing valve without separation of the air from the water and such that the mixture is at least partially depressurized at the pressure-reducing valve such that the air forms microbubbles in the water.

A system and method for circulating water in a swim spa. A recessed chamber formed in the shell of the spa defines a space to hold at least a portion of a first, upper horizontal water propulsion device and at least a portion of a second, lower vertical water propulsion device. The first, upper horizontal flow of water is combined with the second, lower vertical flow of water to create a third, horizontal flow of water. The resulting turbulence is lower, creating a more laminar flow and better user swimming experience. Jet bodies with side intakes may maximize capacity of the water propulsion devices.

A spa includes a shell having at least one cavity, the spa shell being configured to hold a volume of water, at seat insert having a plurality of hydrotherapy jets, the seat insert being received in the at least one cavity and defining a space between the seat insert and the shell, and a drain associated with the at least one cavity for removing water from the space between the seat insert and the shell.