My pool fills the hot tub and then overflows into the pool. So when the pump shuts down the hot tub level is full. In the 8 hours between pump cycles the hot tub seems to drain / leak 3 - 4 inches of water. This appears to have started about 6 weeks ago. Can't really tell if it leaking back thru the system into the pool or if I have a break in the line. I don't find any wet spots in the yard but most of the piping is below the pool deck so it could be leaking below concrete.
Any ideas what could be happening? Is there a check valve I should look for that may be clogged?