Question on pipe diameter exiting from Hayward through wall skimmer

[Idigress]

What is the correct pipe diameter for exiting at the bottom of the skimmer? Ours seems to be 1.25" but I've read where others have used 1.5" diameter PVC. The picture shows a dry fitting of the 1.25" pipe. Looks like the external threads of the skimmer is the point we need to join up instead of the internal threads...so, what fitting or coupling do I need?

 

[Pne123]

The threads on the Hayward skimmer is 1 1/2 fnpt. I bought a 1 1/2 npt x 1 1/2 slip adaptor and ran 1 1/2 pipe. Looks like you have a 1 1/2 npt x 1 1/4 reducing adaptor.

 

[Idigress]

Ah, makes sense. Thanks for responding