If your spa jet is popping out of it's socket, this could be caused by a one of the following different factors;
Your jet face is not screwed in place properly. To resolve this, gently push on the jet face and screw it clockwise to tighten it back up.
The seal on the jet body could have worn or broken
The jet body could be damaged or not sitting in position correctly
If you need to replace your jets or jet body, you will need to measure your jets accurately to ensure you get the correct size replacements.
Please see the video below on how to measure your spa jets.
Read the detailed article on the Spa Store site.