Gentlemen, first off, this is a first time poster. Just found the site. I have pool issues, but none more important and dominating than this one:
I have a spa leak. The pool does not leak. I have turned off the pool and the spa, and the spa went down. Way down, like, to below the light niche. The pool stayed constant. So, of course, everyone said to me, "Your check valves are leaking water back into the pool. Okay. I replaced the check valves. Still... the water went down. "Well, you have a leak in your backwash valve." So, I replaced and lubricated all the rubber gaskets. Did not stop the leak and I checked the drain at the front of the house, anyway. Dry.
I drained my pool this spring (we'd had a bad storm with some large limbs fall in and it was a bad mess) and left it open for a week. Drained the spa, too. Pressure washed the sides, etc.. While I had this opportunity, I dug out from around the light niche and the drains and epoxied those, plus I pulled the light and sealed up where the pipe opening. I filled the spa to see if the water would come back through the returns. Nope. Not a drop. The spa, of course, lost water.
I filled the pool back up and started the season with a leak somewhere. Soon, my 2HP pump motor of 15 years failed and I replaced it. Oh well. 15 years, I suppose, was pretty good.
Anyway, I have inspected all my fittings of the exposed pipes. No leaks. I checked for air bubbles in the filter basket through the clear lid. None. I have noticed, though, that I do not get any water leaking when the pool runs. I recently ran it for three straight days non-stop. It did not leak and stayed steady at the same amount of water consistently. However, last evening I turned it off at 10:00 PM and then inspected it again this morning at 7:30. The spa had gone down about 2.5".
As a last mention, the pool sits above the pool equipment. I live on a slight hill and the pool is higher than the house, where the equipment is installed. Any suggestions would be welcome!