According to the total hardness value of water, the total hardness 0-30ppm is called soft water, the total hardness above 60ppm is called hard water, high-quality drinking water does not exceed 25ppm, and the total hardness of high-quality soft water is below 10ppm. Therefore, it is still recommended to install water softeners, such as Nobana series water softeners. The imported softened resin is used to effectively remove calcium and magnesium ions in the water, which is not easy to form soap scale. The fresh water quality is precisely controlled, so that the water quality can return to the right softness and hardness, and the bath experience is enhanced.