Aerators are generally used in Australian aquaculture ponds day and night at full speed
without regulation. This situation is untenable in view of climate change, as energy
conservation becomes an essential issue for all industries, including aquaculture. Variable
speed performance curves were developed for the paddlewheel aerators that have been
employed on Australian marine aquaculture ponds so that speed may be actively adjusted to
match pond water quality requirements. Results show that speed of rotation is a significant
factor effecting the performance of a paddlewheel aerator. Of particular note was the
observation of backsplashing when kinetic energy (pumping head) was greater than the
radius of a paddlewheel. The process of backsplashing is readily identified when whitewater
is seen flying above a paddlewheel. It is hypothesised that backsplashing dilutes the
oxygen-starved water entering a paddlewheel, thereby degrading the operational efficiency.
Backsplash breakpoint speed is related to paddlewheel diameter. Aerator users can reduce
backsplash by changing mechanical gearboxes or using a variable frequency drive