I have an Image Paradise spa. The center spinning pieces of the small jets are popping out. How do I replace these and where can I get parts? Does the entire jet need to be replaced or just a clip that holds the spinning piece in?

normally the center part (the part that you turn to adjust) can be removed by rotating it counter clockwise. They frequently are hard to turn and require a tool to remove them. I use a really large plier designed to remove automotive oil filters. The you typically buy the whole new jet and replace it.