[calspa_newbie]

I have a 2002 Cal Spa. It has been working great with no problems since I bought it about3 months ago. We were using it one night and when the jets got turned on (high) the jet valve closest to the skimmer blew the diverter cover off, poped the valve insert up and started spewing water like a fire hydrant! We shut it off and saw that the valve body had slipped down into the hot tub shell so that just the rim of the threads were showing. Then we took the panal off and pushed the valve body back up through the hole enough so that the diverter cover could be screwed back on. I should add that we had to push very hard to get it to slip through just 1/2 of an inch.
So we thought we had our problem solved until we turned the jets on high again. It ran fine for a few seconds and then it poped the cover off again and fell back down into the shell (about 1/2 inch). We checked the threads on the cover and the valve body and both were visibly fine nothing was stripped or even looked worn.
The only thing I can figure is that there is too much pressure pulling the pipe down and the diverter cover is too flimsey to hold on. What I don't understand is why all of a sudden? Should there be a support of some kind holding the valve body through the shell other than the diverter cover? If any one has any idea what would cause this please help?
Coencedintaly the optic lights that had just worked fine earlier that night would not turn on right before this happened. Not sure if they are linked or not so if you have any advice on that I would love to hear?
Thanks, calspa_newbie