the invention relates to a method of treatment of bodies of water such as recreational pools , spas and hot tubs with maintenance doses of water treatment chemicals to achieve consistent sanitization and aesthetically pleasing levels of properties such as turbidity . the amount of the maintenance doses is based on the volume of water to be treated in order to achieve hygienic and clear water . the method can be automated for accurate , consistent and safe treatment of water such as found in swimming pools , spas or hot tubs .