[TwoTankAmin]

I am not sure re the blow off, but I have run my tank down to empty and not had problems. In fact the tank has had very few deaths cept from old age.

If you can not screw that manifold directly into the the regulator out (you need to remove the nipple/valve), take the manifold and the regulator into a local plumbing supply place. Tell them you need an adapter to connect the two. I had to do this so I could screw my needle valve into the regulator out. The piece cost me a couple of dollars.