Schematic of the experimental setup used to perform simultaneous visualizations of concentration and qualitative pH fields, flow rate measurements, and voltage measurements under galvanostatic conditions. The frit was epoxied into a 5 mm square, clear borosilicate glass channel, and coiled platinum wire electrodes were positioned at variable locations along the channel. Visualizations were performed with an inverted epifluorescence microscope, and flow rate measurements were performed with a microflow sensor. Large diameter reservoirs were filled to equal heights to insure a negligible external pressure load.