Xref: kermit rec.ponds:145908

You are right, in that the water do indeed come from the opposite end of the hub. I
saw that diagram and thought that the end was not capped, letting the water to flow
up too.

Ann in Houston wrote:

No, if you'll look again, I think you'll see that the supply hose goes into
the free end of the slotted pipe and then the water percolates up through
the rock like a common old septic field.