Is it important to prepare your spa for the winter?
Any hot tub is subject to freezing during colder weather. If any water is left in a spa (or in the lines, pumps, or fittings) that is not operating properly, the water can freeze, which will cause serious damage to your hot tub. And here’s the important part: Any damage that is caused by freezing IS NOT covered by your warranty.
Your best bet is to leave the spa running. All spas with a computerized control center have a “freeze protection mode” that prevents damage to the spa in cold temperatures.