A method for calibrating, auditing and controlling a liquid dispensing system , comprising: taking a portable device in hand having a flow meter (42; 43) and a hand-held controller , the flow meter (42; 43) being operably connected to the hand-held controller ; removably connecting an inlet (38; 39) of the flow meter (42; 43) in-line with a liquid input to the dispensing system ; operating the dispensing system ; and acquiring liquid flow information from the flow meter for the liquid input; wherein the portable device comprises a first and second flow meter and the step of removably connecting: a. the inlet (38; 39) of the first flow meter (42; 43) to a liquid product input; and b. the inlet (38; 39) of the second flow meter (42; 43) to a liquid diluent input; wherein the inlet of the first flow meter has a quick-connector adapted for connecting the inlet of the first flow meter in-line to a first liquid input of the liquid dispensing system; and the inlet of the second flow meter has a quick-connector adapted for connecting the inlet of the second flow meter in-line to a second liquid input of the liquid dispensing system; further comprising the step of calculating a dilution rate using liquid flow information from first and second flow meters , and the step of calibrating the liquid dispensing system based upon the measured liquid flow information. taking a portable device in hand having a flow meter (42; 43) and a hand-held controller , the flow meter (42; 43) being operably connected to the hand-held controller ; removably connecting an inlet (38; 39) of the flow meter (42; 43) in-line with a liquid input to the dispensing system ; operating the dispensing system ; and acquiring liquid flow information from the flow meter for the liquid input; wherein the portable device comprises a first and second flow meter and the step of removably connecting: a. the inlet (38; 39) of the first flow meter (42; 43) to a liquid product input; and b. the inlet (38; 39) of the second flow meter (42; 43) to a liquid diluent input; a. the inlet (38; 39) of the first flow meter (42; 43) to a liquid product input; and b. the inlet (38; 39) of the second flow meter (42; 43) to a liquid diluent input; wherein the inlet of the first flow meter has a quick-connector adapted for connecting the inlet of the first flow meter in-line to a first liquid input of the liquid dispensing system; and the inlet of the second flow meter has a quick-connector adapted for connecting the inlet of the second flow meter in-line to a second liquid input of the liquid dispensing system; the inlet of the first flow meter has a quick-connector adapted for connecting the inlet of the first flow meter in-line to a first liquid input of the liquid dispensing system; and the inlet of the second flow meter has a quick-connector adapted for connecting the inlet of the second flow meter in-line to a second liquid input of the liquid dispensing system; further comprising the step of calculating a dilution rate using liquid flow information from first and second flow meters , and the step of calibrating the liquid dispensing system based upon the measured liquid flow information. the step of calculating a dilution rate using liquid flow information from first and second flow meters , and the step of calibrating the liquid dispensing system based upon the measured liquid flow information. <EOS>