This paper focuses on the characterization of an electrochemical flow cell designed for capacitive desalination, by using the Fe-III(CN)(6)(3-)/Fe-II(CN)(6)(4-) redox couple as an electrochemical probe. A relationship between the potential scan rate and the electrolyte flow rate has been first established by defining a dimensionless number, theta. Depending on the theta values, two regime domains-dependent and non-dependent from the flow rate-have been defined. The dimensionless number theta was found to be of great help for defining the suitable flow rate for several carbon based electrodes exhibiting different surface area, using Fe-III(CN)(6)(3-)/Fe-II(CN)(6)(4-) redox couple as an electrochemical probe. The proposed electrochemical analysis is a way to optimize the performance of an electrochemical flow cell for capacitive desalination applications.