Abstract: A spray-type dispenser for on-demand dispensing of a solid block of chemical retained within a container in the form of an aqueous chemical solution of substantially constant concentration, comprising: (i) an upwardly dispoded spray nozzle, (ii) a three-dimensional support screen for supporting the solid block of chemical above the spray nozzle, and (iii) a housing enclosing the spray nozzle and support screen; the housing and support screen defining an annular cavity. In operation, a container retaining a solid block of a water-soluble chemical is placed within the dispenser such that the support screen contacts the chemical but not the container; thereby allowing the container to descend, by force of gravity into the annula cavity as the chemical retained therein is dissolved.