Dean all good comments however I do know better. There was no air in that system. I had the hose bent in a manner that we had no cavitation. You are correct any air would greatly reduce the efficiency of the pump and the venturi system.

@@KeeneEngInc Hey ,I wasn't trying to pull you down ,it's just if you study the effects of a boat prop in a small tank you see how it effects the prop cavitation is greatly raised due to sloshing water trapping air which swirls about the tank ,i think some colleges have put the study up on here in slow motion footage,i read it when studying prop design ,what helical draw work have you done ? Like eddy effects with positioning jetting ,such as 19° merging also 19° crossing flow at higher pressure and lower pressure ,the effect like propulsion without a prop ,sort of like new propless jet drive type ,where there is a spinning prop the water is squeezed through water positioned jets instead,so be like an eddy dredge pump effect without a prop ,advantages are better stronger venturi plus no prop to get things lodged in prop to block it