re: #381 Marvo76 Doubt it’s Air injection that is used to halt Cavitation. Cavitation is caused by the collapsed of airbubbles created as a result of pressure differentials created in the prob forcing water. More air injected would increase friction increasing the pressure differential and causing increased cavitation(the collapsing of the cavities in the water created by the thermodynamic reaction to pressure on one side droping below the waters vaporization point.) Best way to limit cavitation is to inject more water on the lower pressure side and having blades which have very low friction.