Plunge recommends initially treating the water with a chlorine and bromine-free oxidizer and sanitizer (all part of their maintenance package) and then checking regularly using test strips to make sure your water quality is good. Depending on the hardness of your water, you might also want to add a softener. Note that using the water treatment products is optional but recommended. Without the products, depending on your water quality and usage, you might have to change the water once every one or two months.