A method for controlling a pH of a solution, the method comprising: a.) selecting a target open circuit potential based on a target pH for the solution; b.) measuring an open circuit potential of two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) in the solution while no current is being applied between the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822); and c.) iteratively performing the following steps: i.) selecting an amount of current based on the measured open circuit potential in order to minimize a difference between the measured open circuit potential and the target open circuit potential; ii.) providing the selected amount of current to the solution via one of the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822), thereby causing an electrochemical reaction wherein one or more redox active species in the solution generates or consumes hydrogen ions, thereby changing the open circuit potential of the solution and the pH of the solution; and iii.) measuring the open circuit potential of the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) in the solution, wherein the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) comprise a sense electrode and a reference electrode, wherein the sense electrode is configured to also function as a working electrode, and wherein the reference electrode is configured to also function as a counter electrode. a.) selecting a target open circuit potential based on a target pH for the solution; b.) measuring an open circuit potential of two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) in the solution while no current is being applied between the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822); and c.) iteratively performing the following steps: i.) selecting an amount of current based on the measured open circuit potential in order to minimize a difference between the measured open circuit potential and the target open circuit potential; ii.) providing the selected amount of current to the solution via one of the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822), thereby causing an electrochemical reaction wherein one or more redox active species in the solution generates or consumes hydrogen ions, thereby changing the open circuit potential of the solution and the pH of the solution; and iii.) measuring the open circuit potential of the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) in the solution, wherein the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) comprise a sense electrode and a reference electrode, wherein the sense electrode is configured to also function as a working electrode, and wherein the reference electrode is configured to also function as a counter electrode. i.) selecting an amount of current based on the measured open circuit potential in order to minimize a difference between the measured open circuit potential and the target open circuit potential; ii.) providing the selected amount of current to the solution via one of the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822), thereby causing an electrochemical reaction wherein one or more redox active species in the solution generates or consumes hydrogen ions, thereby changing the open circuit potential of the solution and the pH of the solution; and iii.) measuring the open circuit potential of the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) in the solution, wherein the two or more electrodes (2, ITO 81 - ITO 84, 242, 815 - 817, 820 - 822) comprise a sense electrode and a reference electrode, wherein the sense electrode is configured to also function as a working electrode, and wherein the reference electrode is configured to also function as a counter electrode. <EOS>