The fluorescence-based imaging technique developed in this study was applied for better understanding the water splitting electrochemical processes. The detrimental effect of the rapid and dramatic pH changes at the electrode surface is due to the poor OER and HER under acidic and basic conditions, respectively. At large inter-electrodes distances, the large increase or decrease in the pH at the electrodes surroundings will have a significant detrimental effect on the overall water splitting performance. However, the point of interest is if the electrodes are close enough, at certain inter-electrodes distances, that the acidic and basic fronts developing