I used 3/4" bulkheads, 3/4" sch 40 pipe.
I left the overflow unglued in the tank so I could take apart and clean
i used 1 1/2"pvc
reduced to 3/4" sch 40.
at the coupling in the middle I glued in a knockout (a plug) to separate the two sides.
my teeth on the overflow are 5/16 wide by 1/2" deep and I used a table saw to cut them in.
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