What’s this for?

[sreed07]

On my return there is a little hole before the jets that water squirts out of and across the top of the water. I’m assuming it’s meant to be there, maybe to relieve pressure or to aerate at the top? I’ll include a picture of what I’m talking about.

 

[Hydrored]

It's to break a siphon when your return pump is shut off

 

[sreed07]

It's to break a vacuum when your return pump is shut off

Ok so it’s normal for a lot of water to be coming from it while the pump is running?

 

[Yates273]

Yes you will bet water coming out totally normal. Like Hydrored stated it’s as siphon break

 

[fish farmer]

Make sure to occasionally clean this hole so it doesn't plug.

 

[homer1475]

+1 for siphon break, and +1 for keeping it clean if you don't want a flood.