Among other things, a spa includes a spa shell and a water feature disposed on the spa shell. The water feature includes a ridge disposed in an interior area of the spa shell and having a top disposed near a water line of the spa shell. The water feature also includes a water inlet disposed adjacent to the ridge opposite a main body of water area in the interior area of the spa shell, the water inlet being placed lower than the top of the ridge. In addition, the water feature includes a slope descending from the top of the ridge in the direction of the water inlet, the slope having a patterned top surface configured to interact with water flowing over the ridge, down the slope and toward the water inlet.
