OK, no obvious obstruction on the reverse flow with the garden hose, BUT there was a leak coming from the top of the Jandy valve at the inlet to the pump basket.

Could this be sucking air in during normal operation? Water flow into basket during normal operation is so low as to actually see the flow out of the inlet opening. Prior to all this, flow was never seen because the basket was always full.

I hope I am explaining this so anyone can understand what I am trying to get across, because I certainly do appreciate the help on this forum.