This paper presents a study conducted to develop guidelines for the design of an air bubble destratification system, with particular concern given to plume spacing. To investigate the effect of plume spacing on the destratification efficiency of the system, we first conducted a dimensional analysis that included major variables in bubble hydrodynamics. Then, we conducted laboratory experiments with various plume spacings and water depths under non-linear stratification conditions, and we evaluated the destratification efficiencies. Our results showed that the highest efficiency was obtained with a plume spacing of 0.75 times the water depth. Our study has shown that the overall efficiency of an air diffuser system can be increased by changing the spacing between diffusers and that plume spacing should be a major design parameter for future air diffuser systems.