Rext under low-and high flow rates (Figure ) shows that the acclimation times are 6 to 11 hours at QT=1 mL h -1 but only 4 to 7 hours at QT=10 mL h -1 . We estimate a 4.5-to 18-times reduction in experimental time using the flow-assisted long-hold approach compared to multi-cycle acclimation over three fill/deplete cycles per external resistor in a bulk MFC. We believe that studies focused on the degree and timing of the voltage recovery can provide insights into the specific nature of the biological process(es) that occur in response to acclimation, e.g., biofilm growth, cytochrome or other protein expression, and shifts in metabolic states, among other factors.