I plumbed my 65G AGA Mega Overflow several weeks ago. I initially used 1 1/4" ID tubing. This fit well over the overflow drain and the 1"
PVC input connector of my
sump. However, I had lots of gurgling caused by the water hitting the top edge of the
PVC sump pipe as it reached the end of the tubing.
I finally went with all 1"
PVC. The only issue I had was attaching it to the drain pipe which was really seemed to be designed for tubing. A
PVC connector for 1"
PVC actually has an ID of close to 1 1/4" so it fit over the drain pipe but was a little loose. To prevent leaks at this connection I put about 2 inches of 1 1/2" ID tubing around the
PVC connector/drain pipe joint and secured it with some clamps.
I have been very happy with the result as there is very little noise. I think the 1"
PVC is the way to go.