I assume you are using this with the "Ace" system - if so, then the good news is that you don't have to change water as often. But the above is good advice if you don't have soft water available: buy a portable softener.
Also, be aware that if you have a regular household water softener, or you get a portable unit, you will need to establish the correct amount of salt to add, because it will be different than the little charts on the bottles and/or in the manuals. I am in SoCal and have several customers who filled their tubs with soft water (from a softener) and had trouble until they found the correct amount of salt needed in their specific tub. Once that was dialed in, they got good service out of their Ace systems, and their tubs.j
What we did was to add about half the recommended amount of salt, wait for it to dissolve and mix (couple hours) and then let the system do a "salt test." It is actually testing the
conductivity of the water, and not the salt level (the test strips do test salt level). Next we added salt a 1/4 cup at a time until it was in the green on the "salt test." Once it tested in the green, we WROTE DOWN the exact amount of salt we had added so we had the info for next water change.
With the salt level in the green, the system comes on-line, and you are good to go.
HTH