Looks clean! I wouldn't even bother gluing anything if it's stays in the reservoir. You'll never be above the pressure needed to worry about glued joints. Anything outside the tub, I would definitely glue. My hose fitting stays in my reservoir too.
So your hose connection, that's meant to help stir up water but also to hook up your python hose to fill your tank, correct? You could install a plastic quick connect there.
The only thing you need to worry about is head pressure. A cheap Vivosun 400gph would be fine for this use. Probably even smaller, but would just take longer to fill.