Dear sir or madam, We have owned a Softub Resort for just about four years. It was always annoying to have to change the water every three months and constant checking of the pH and chlorine level as well as the unpleasant chlorine odor. With a similar product (AquaFinesse) you also have to regulate the pH level, and in addition, work with small quantities of chlorine and every 4 - 5 months, the water had to be changed. Two years ago I finally fond...