It's below the OF box, behind the tank. There wasn't a whole lot of room underneath to get the gate valve with its neighboring unions to fit.
I'm a night-shifter! I've got the booze-a-hol thing down pat, but I'll never get enough sleep until I'm dead! ;Hilarious
Yeah, so that's tricky. I bought the 1800gph Modular Marine overflow and I really do love it (my problems are likely user-error). But I forget to ask them to size down the drain bulkheads, so the bulkheads are 1.5". I was able to reduce to 1.25" inches below the box, but the standpipes on the inside of the box still need to be 1.5" PVC, which makes everything in there super tight. My primary drain is just a strainer. The emergency drain is just a straight pipe. The secondary drain is set up as a U-shaped standpipe but because of it having to be 1.5" pvc, I have it as tall as it will go while still being able to get it out. If I try to raise it even by a quarter inch, I'll never be able to remove it. So it does lurch probably only an inch or two above the strainer. I'm not sure if there's a PVC fitting I could use to reduce the 1.5" pvc down while still maintaining the u-shape and not taking up any more room. And would having a secondary drain that has a smaller aperture leading into a bigger body before draining out of the box make things noisy?