Free Pond Aeration calculator with clear step-by-step results.
Aeration demand comes from fish respiration and sediment oxygen uptake, both of which rise with temperature while the water's capacity to hold oxygen falls - the reason summer nights are when ponds crash. Dividing demand by the aerator's oxygen transfer rate gives the power needed.
Oxygen saturation
mg/L = 14.6 - 0.35 T + 0.004 T^2
Aerator power
kW = oxygen demand kg per hour / oxygen transfer rate kg per kWh
Photosynthesis stops after dark while respiration continues, so dissolved oxygen falls all night and bottoms out just before dawn. Aeration must be sized for that minimum, not the daily average.
Surface fountains are poor aerators relative to their power draw. Diffused air from the bottom or a paddlewheel transfers far more oxygen per kilowatt-hour.