A method for obtaining a chemical concentration from a chemical composition and a fluid includes introducing the fluid through ports in a manifold diffuse member positioned adjacent a chemical composition and adjusting, with a fluid valve, characteristics of the flow of the fluid through the ports in the diffuser manifold to obtain and maintain a chemical concentration. The amount of liquid allowed through the ports modifies the turbulence of the liquid, thereby modifying the erosion rate of the chemical composition. An apparatus for adjusting characteristics of the flow of a fluid contacting a solid product to form a product chemistry includes a diffuser manifold having a manifold diffuse member comprising ports therethrough and a fluid valve for controlling the flow rate of a fluid moving through the plurality of ports and diverting the fluid through various flow paths.