3/4" elbow with a 1/2" pipe thread outlet. This kept my drain at the bottom. I installed the pressure relief valve further up and the PEX adapter at the top.
Below is a picture of the old piping for reference.
|PVC pipe running from the barrels to the house.|
|PVC pipe going through the ventilation screen. Most of the pipe is buried under an inch or two of dirt.|
|The pump was able to move the water from the barrels through the hose.|