Abstract: The apparatus consists of a mechanism for supplying water to the toilet and flushing water into lavatory, a vessel with solid cleaning detergent in a saturated solution, a portioning mechanism and a water supplying mechanism. The portioning mechanism supplies equal portion saturated or strong detergent solution into tank with every flush. The water supplying mechanism adds water into the vessel and keeps high level of the detergent solution in the vessel. Because the vessel consists several solid detergent tablets and it is full of saturated detergent solution, and because the portion of the detergent solution pouring into the toilet tank is a small fraction of the volume of the solution in the vessel, and an equal portion water has been supplied after each, the solution of the detergent is always saturated. Because the portion of the detergent solution dispensed is always equal the concentration of the detergent in the water of tank is always equal until the last tablet is dissolved.