Built-in Custom Hot Tubs Let Colley’s Pools & Spas install a custom inground hot tub in your yard. We have several models to choose from. These hot tubs come complete with a power pack and gas heater that can be installed in your basement or outdoors. Then, have your hot tub finished off with concrete, brick, or a flagstone border.   As an addition to your inground pool or on its own, enjoy relaxing in your custom inground hot tub.