I have a 20K gallon in ground pool/spa spillover. Around 2 weeks ago, I noticed that the water in the spa was lower than normal and the jets would come on but with very weak pressure. I added water to the pool but did not retest the jets. I go out of town for 4 days and when I return the SPA is drained to below the jets. So I turn the valves to spa fill mode to allow water to flow from the pool back into the spa. This fills it back up to the normal level. About 6 hours later the water in the SPA has leaked out again. I tested to see if the water was flowing back into the pool but it was not as the water level in the pool remained the same. I checked around the pool and around the pool equipment area for soggy ground. There is no sign of water leakage from the filter pump, etc. Does this mean that I have an underground leak and what is the average cost for detecting and fixing such a leak?
20K gal, IG Tahoe Pebble, Jandy Stealth Pump 2HP, Jandy Cartridge 460 Filter, Jandy Aquapure SWG, Polaris 3900 Cleaner