Abstract: An apparatus for treating bodies of water such as lakes to correct chemical, biological or other imbalances in the aquatic environment by accurately dispensing a treatment agent into the water is an amount based upon the volume of water being passed over and continuously determined by detection means for the speed of the boat or vessel carrying the dispensing means and the depth of the water being passed over. When the water is being neutralized by a chemical addition, the pH of the water may also be continuously monitored. A boat particularly designed and adapted for practicing the method is also disclosed. The boat includes a main tank partially supported or floated by the water at least when the tank is located and also stabilized and partially or additionally supported by lateral inwardly and outwardly adjustable pontoons when loaded. The boat includes sparging, or mixing and above or below water dispensing means to dispense the treatment agent.