Cusser

I would stuff in fiberglass insulation. Wear gloves and long sleeves, and dust mask.

To get that union at the pump loose, I've had GREAT success with Vise Grip 12LC https://www.google.com/search?q=vise+grip+12lc&spell=1&sa=X&ved=2ahUKEwjvvJSCg7X5AhX_K0QIHel-BlcQBSgAegQIARAz&biw=1344&bih=615&dpr=1.36

I cannot recommend any - because since getting my spa in 1988 I haven't used one. I just hose off the filter, and change it out once or twice a decade. I think there are cleaning devices available to purchase, but I've never used any or even any brushes. Remember - ANY detergent will causing foaming issues until the end of time....

I'd focus on the seams within 6 feet of the observed leak. Remember that a leak can also travel. I had a leak at a poorly-manufactured/sealed seam on 3-month-old above ground pool liner, and had a difficult time getting manufacturer to admit fault. They wanted me to find Sharpie-written serial number and the leaky part and ship that to them for consideration; they would not allow one of their local dealers to come over to take a look. I ended up patching that myself which lasted a few years, then my daughter and I replaced that with the one finally sent out as replacement.

I would sand a small area around the chip and try marine epoxy if it was my spa.

I find Irwin Vise Grip 12LC very handy, couldn't live without it (I own 2).

I can't help, my "old CalSpa" was manufactured in 1988 !!! I suggest you call CalSpa, but don't be that optimistic that they can help, it seemed to me in my couple of calls over the years that their "tech help" wasn't so good....

That leak should be straightforward to fix. Either cut off the old fitting (if hose is long enough) or study up on the heat gun technique to loosen the glue and pull off the leaking fitting.

If you try this: Don't mix, danger !!!! One at a time, rinse in between.

Yes, spa covers are expensive, I'm due for a new cover myself. I have a 1988 CalSpa, and am on at least my 4th cover. My spa sits on my covered patio in Arizona, obviously gets no snow and very little rain; however the "winter" sun does hit on the cover. Theoretically, if the styrafoam slabs are not waterlogged, a cover could be made to fit; but you'd obviously be talking about a local company, unless you know upholstery....

Post pictures. And don't be a girly man !!!

I agree that there's been or still has a leak, and that calcium carbonate has deposited from the water. Vinegar-soaked rags would be my choice to try to remove the deposit, but the leak still may need addressing.

I guess I've read that 110V spas need to heat quite a few hours per day. If so, won't that generator be running a lot?

I have a 1988 CalSpa with a small leak I have been unable to locate (one side is 8" from house wall). So about a decade ago I started using Fix-a-Leak once or twice a year, and it does work. https://www.fixaleak.com/

Nice photo of the leaky drain valve