I have a 1996 HS HighLife spa that is leaking from below at a rate of about 6 to 8 inches in 24 hours. The leak does not seem to be originating in the equipment compartment. It is sitting on a high deck so i can tell that the water always exits from the same place. I have searched for cracks in the tub and found nothing obvious. I replaced the motomassage jet recently which required me to remove the cover plate. I noticed in the process that there is a joint in the bottom of that compartment that seems to be sealed with a type of hard caulk or fiberglass. A piece of the caulk was floating around in there. The joint does not appear to be cracked where the caulk came off and the place where the water is exiting underneath the spa is on the opposite side from the motomassage, more like under the filter. Assuming I should try to recaulk this anyway, what should be used?

I really think there is a plumbing leak internally. If I need to start digging for this leak, how do I get the sides off? The cedar siding seems to be glued on to fiberboard. Do you just rip off the cedar planking and replace it with new? The local Hot Springs dealer said it is not worth it for them to try to find the leak on a 13 year old spa, but if i wanted to try, i should heat up the water then start digging in the foam and go toward the heat. Other posts here talk about entering from underneath the spa but that would have to be on an empty spa.
All suggestions welcome! Griffin

Did you check the light lens? If it leaks the water does not come out of the motor compartment, it seeps into the foam and comes out elsewhere.

Also, recheck for cracks especially at the backside of the motor compartment around the light lens and the backside of the shell where it curves. In a highlife, there is a fair amount of shell exposed in there. Sometimes the cracks are not visible on the inside of the shell but you can see them much easier from the back.

First get a large bottle of blue food coloring like a 1/2 pint or so. DUmp it in the water and let it run and sit for 24 hours. The dye will leak out and discolor the foam insulation where the leak is. It may also discolor any cracks and allow them to be seen. Then drain the tub. And here comes the tricky part. Stand it up on its equipment end so the weight is on the bottom. You can then remove any bottom membrane and dig out the insulation following the dye stain back to the leak.

Once you find the leak if its a crack take a small drill bit, like 1/16" and drill into the shell at each end of the crack to isolate the crack and stop it from spreading. You can drill thru the shell but be careful to stop when you penetrate so you don't drill a hose. Next take a dremel and groove out along the crack topside. You will them need some epoxy or fiberglass (whatever material is compatible with your tub shell). You can check with the manufacturer to see what they recommend and/or sell. On the back side scrape the insulation off down to the shell using a chisel. Take some of the epoxy and some fiberglass mesh and make a sandwich on the bacside of the tub as reinforcement. Then take some of the epoxy and fill the front side holes and groove. Let it dry and fill it.