I’ve used a jetted tub outdoors for over 20 years in Alaska — summer and winter. It used to be a hassle caring for it in subzero temperatures, but not any more using Silk Balance. It keeps the water clean, smelling good, and the best part is I know it’s keeping all the plumbing in good condition with no buildup. Just a 4 oz. capful poured in once a week, how nice and easy! When you think of all the chemicals you don’t need any more it makes Silk Balance affordable. I actually wouldn’t care what it cost, since it keeps the hot tub clean and ready to use with no worry about pH balancing. Thanks for making such a great product!