Return line question

[Flreefer]

1/8 inch would be fine, just enough to let air in to break the siphon.

 

[Reefpete]

1/8 inch would be fine, just enough to let air in to break the siphon.

Cool thanks I'm gonna drill it now and test it tomorrow let all the glue and primer dry properly and wash all the pipes tomorrow before I put it in tank