The ACE Salt Water Sanitizing System is a revolutionary breakthrough in spa water care. The salt water system has never quite been perfected before by others, but the Watkins R&D department has figured out the secret to make this system effective, easy to use and the water comfortable to soak in. This aftermarket option, compatible on all August 2009 and newer Hot Spring spas, has forever changed the spa industry, and we have had overwhelming feedback from our customers about how happy they are that they have this. We have actually had a large number of people trading in their spas just to be able to add ACE to their spa. There is not another system out there that offers a more comfortable, silky smooth soaking experience. Visit your local American Sale and speak to one of our spa professionals for more information about how this is a must have product