I do have spa hose connected to a union on the backwash, I did this so I could connect it when I need it and just use the ball valve to cut off any water in the line when done. I remember doing this with an overflow box, I put a tube in the oline is sucked on it till water started to flow over, same concept? So I'm going to have to suck on the spa hose till water starts to flow correct?
Damn....I know you're strong but to suck all that air?????? Instead of sucking you can shop vac the union or valve. That should start the flow. Turn the handle to waste or rinse during the sucking and back to filter before you turn on the pump.