Here's a picture from the top of the tank. It is a little tough to make out, but the partition I was talking about is on the left. The hole on the right goes all the way through the tank. I just ran the 3/4" return line up through it.
Here's a picture of the basement plumbing. The Steralite container is temporary. I have a 75 gallon for the sump but it currently has a pair of Clown loaches I've had for 16 years so I want to make sure the tank is completely cycled before I put them in.
It was tough to get the pvc through the wall, so I'm fairly limited to keeping the main drain 1". Are you guys saying basically for the main drain cut the Durso off just below the T which would be a couple inches below the weir, cut the ball valve in the basement off and replace it with a gate valve and finally replace the other standpipe with a taller pipe just to the top of the overflow? Would it help to increase the main overflow pipe above the 1" bulkhead with 1 1/2" pvc? How do you tune the gate valve?