Have an in ground spa and pool. Spa is raised above pool by a couple of feet (see pics attached). Some mornings before the pump comes on I have lost half the water in my spa (about to the jet line - approx. 500 gallons). Others mornings there is negligible water missing. Does not seem to be temperature related. I have checked the jets for leaks using dye. I have run many tests and have determined that if I allow the pump to be turned off at the end of the day by my Jandy system, I lose half the water by the next morning. If I manually turn it off at the end of the day before the timer does, I lose almost none by the next morning. Sounds weird, I know, and as an engineer, this is keeping me up at night. I have methodically verified this multiple times. Regardless, the pool level does not change up or down. I have verified that regardless of which method I use, the valve positions do not change on turn off and turn on. Any help or ideas would be appreciated. Thanks.