The core objective of shutting down a swim spa tub in winter is singular: Ensure there is no water in the system that can freeze. This typically requires: • Draining the water • Cleaning the filtration system • Releasing residual water from the pipes

In most cases, this is perfectly normal. A swim spa tub is essentially an open water system, especially when installed outdoors, where the water surface is directly exposed to the air. As long as the water surface is exposed, evaporation is inevitable.