Hello,

My Sundance Spa has developed a thumping noise. It sounds like something behind the redwood skirt bumping into the fiberglass shell. It's a very steady thump, thump, thump....about one thump per second. Any ideas what this could be? It's a dull thump, like you would expect if you made a fist and hit the shell with the side of your fist.

I removed the side skirt panel hoping to locate the problem, but there's so much foam insulation, there's practically no way of getting any closer to the source of the problem. Any suggestions?

Thanks,
Garry