somehow, prior to my ownership , small stones clogged 2 spa return jets. With a coat hanger I dislogged some leaf debris and got some water flowing into the spa but then found something hard was still at the opening of a jet. The pool / spa is from around mid 1990's.
I removed the plastic jet(s) with a 1/2 " socket on a 6" rachet extender. It was easy to remove as it must have only been hand tightened the almost 20 ish years ago , thankfully.
The jet had a small stone logged inside the jet, stuck at the opening. I pushed it down the jet tube with the head of nail tapping on the nail point until it dislogged. I then cleared the other jets the same way though in those the stones fell out more easily.
the jets with stones all had weak water flow.
I hope this can help someone else. I've been helped here before.