located adjacent the opposite ends of the standpipe 26 the chemical solution within chamber 36 thus flows outwardly through the opening 38 so as to be intermixed with the surrounding body of water in the desired proportion and the standpipe is refilled within clear water osmotic pressure then causes some of the chemicals in container 16 to flow upwardly into the standpipe 26 so as to replace the chemical solution therein in the present invention the container 16 is preferably only partially filled with the dry chemical 32 so that upon depositing same in the body of water sufficient water will flow into the compartment 31 to result in the formation of the saturated solution 33 this saturated solution 33 continues to exist so long as a quantity of chemical 32 remains in the dispenser after the chemical has been completely used up then the dispenser can be readily removed from the toilet tank and disposed of or as an alternative the dispenser can be refilled with a selected quantity of chemicals to demonstrate the desirable performance of the present invention experimental tests were conducted on a dispenser according to the present invention and utilizing a standpipe of substantial diameter and axial length therein a similar experimental test was conducted on a dispenser of substantially identical construction but employing therein a large diameter opening rather than a standpipe these experimental tests clearly indicate the substantially improved performance achieved by using a dispenser employing therein a standpipe as illustrated in the attached drawing specifically in the first test the dispenser was provided with an eight ounce capacity and initially contained four ounces of calcium hypochlorite the dispenser was provided with a 5 8 inch diameter opening in the.