Abstract: Apparatus and for providing controlled addition of a first aqueous solution having a first concentration of an aqueous chemical species at a first flow rate to a second aqueous solution having a second flow rate to provide a diluted first solution of a desired selected concentration of the chemical species, the apparatus having a second solution sensor to obtain data on the second solution selected from the second flow rate and the temperature of the second solution; a first solution sensor to obtain data on the temperature of the first solution; a pump to effect addition of the first solution to the second solution to provide the diluted first solution; and a CPU (i) to receive the data selected from the second flow rate and temperature data from the second solution sensor; (ii) to receive the temperature sensing data on the first solution from the first solution sensor; (iii) to effect algorithmic treatment of the data from the first and second sensor, to provide pump control data; and (iv) to control the p