[chucktoo]

I was wondering what the faileure mode is.

If the pump - run two in parrellel with check valves ?

If the jet maye two or better still a staged system one on at say 10 psi or what ever is 1/2 the max flow needed and the second at say 15 psi providing the other 1/2 of the flow . If one system fails you still have 50% of the flow worste case and tune accordingly on the conservative side.

I assume this has been done ?

There must be a problem other than it costs twice as much ?

Thanks Charlie