Update

I somewhat finished the plumbing. I need to make some more adjustments.

Returns - everything has been glued together, but the down pipe connected to the 45 is not.



See the herbie drain? That's only 1.5" difference between the primary and emergency. There is a problem with that which I'll get to.



The main siphon has a union then a gate valve.



Here you can see the emergency drain. I also have my tube holder for the dosing pump and ATO.



And then the return pump. It goes from the return pump using flex tubing into the inside of the barb (it does not leak as it runs inside quite a bit and there is no way to pull that tube out now. Then it goes to a barb fitting, flap style check valve to a union.



And the finally the sump. Only enough room for my protein skimmer and a zeo reactor.