Air is drawn in automatically through an air intake adaptor. The rotation of the water/air mixture provides a long contact time with the pollutants resulting in a highly efficient performance. The extremely fine water/air mixture is pumped into the contac 

The AP701 produces a maximum level of air at 750 lts per hour but will be more efficient in most aquariums turned down to 600-650 lts using the tap. This is due to turbulence in the neck of the skimmer drawing foam back into the body