Drilling fluids are used to aid the drilling of boreholes into the earth, i.e. for extracting petroleum oil. The flow behavior properties of a drilling fluid contribute to several important factors for successful drilling of oil wells, e.g. pressure control, maximizing rate of penetration, providing wellbore stability and removing cuttings from the well. Each well is unique, making it important to be able to visualize and control the drilling fluid flow for each application. Accurately measuring the balance of the drilling fluids as a system (barrels-in versus barrels-out) provides important information to the driller and mud logger. It gives for example early warning kick detection and allows accurate monitoring of the mud transport velocity and lag times.