Abstract: A water treatment container for utilization in a tank of a toilet bowl having an upper chamber through which water may circulate; an intermediate wall separating the upper chamber from a lower chamber, the intermediate wall carrying water treatment material which may be used up and if necessary a ballast material, the lower chamber being sealed to be buoyant. The weight of the water treatment material and, if necessary, the ballast, is such as to hold the container in the tank in an orientation where the air chamber is the lower one standing on the bottom wall of the tank. An additional chamber at the bottom of the container having an opening extending to the bottom wall is provided, said additional chamber carrying a water coloring material.