Internal overflow plumbing suggestions

[Mikeeal]

I'm hoping to get suggestions on how to plumb this. Bought this tank second hand and the plumbing was already gone. I've done durso style in the past, but this one doesn't have the room for an elbow inside the box. There's two existing holes, separated by a weir that's open at the bottom. Not sure how to approach this one:

 

[UncommonSense]

This is a very interesting overflow box layout!

I really like the integrated cable/plumbing pass-through hole in the tank! I had a 125g acrylic corner pentagon with a nearly identical pass-through years ago…

— because the odd weir/baffle in the overflow box is open at the bottom, you can treat it like one large water container from a fluid dynamics standpoint! (It just means the bottom of the overflow box won’t ever have stagnant water in it!)

— if this was my tank, I’d pursuit a dual drain “Herbie” plumbing configuration! That is, you’d use the two existing bulkhead holes as drains; one primary drain with in-line gate valve, one completely open emergency drain! (The return plumbing is snuck up through the in-tank pass-through and over the tank rim)

— this plumbing configuration allows you to precisely restrict the primary drain via gate valve until it creates a controlled full siphon, making the tank run near-silently! (If the primary drain ever clogs, the emergency drain takes over/is noisy so you know there’s an issue!)

 

[Mikeeal]

I can dig it, I appreciate the response. It's definitely an older tank, manufactured by TruVu. I agree with you on the dry box, I'm gonna appreciate being able to butt it right up against the wall