In conclusion, this study highlights the complex interplay between gas-liquid hydrodynamics and photon absorption in photoreactor systems. While gas bubbles introduce interfaces that can alter photon behavior, the anticipated photon absorption losses were less significant than expected, presumably due to mechanisms such as reflection, refraction, and total internal reflection. The results demonstrate that the introduction of a gas phase does not necessitate a proportional reduction in liquid flow rate to maintain efficient photon absorption. Smaller gas bubbles enhanced photon absorption by extending the effective optical path length through scattering and reflection effects. These findings, though specific to the experimental setup, have broader implications for optimizing gas-liquid photochemical processes, especially in systems involving non-absorbing gases. The methods used in this study, including the determination of the effective optical path length, offer a robust approach for evaluating and enhancing photoreactor performance across various configurations and conditions.