Abstract: The combination of a passive dosing dispenser, of the type having a reservoir containing a cake of active ingredients which are depleted as water is routed through the dispenser, and an improved hypochlorite cake for use therein. The improved hypochlorite cake provides water-soluble hypochlorites, and additionally contains materials capable of forming a water-insoluble matrix from which hypochlorite salts may be leached out by the water in the reservoir. The size of the cake desirably increases somewhat while the dispenser is in use so that the mass of aqueous hypochlorite which may be poured from the reservoir of the dispenser remains constant or slightly decreases as the active ingredients are used up.