A chemical mixture dispensing assembly for automatically filling a fluid containment with a predetermined ratio of chemicals and water includes a housing that is mountable on a support surface such that the housing is positioned proximate a fluid containment. The housing is fluid coupled to a water source, a first chemical source and a second chemical source. A mixing unit is positioned in the housing and the mixing unit mixes a predetermined volume of fluid from the first chemical source and the second chemical source with a predetermined volume of water from the water source to produce a fluid mixture. The mixing unit dispenses a predetermined volume of the fluid mixture from the mixture outlet to fill the fluid containment with the fluid mixture.