I hope this is in the right forum area.
I have a 25Kgal spa/pool combo (IG) - last night for the first time the spa seemed to empty itself to approximately pool level.
I checked the valves and everything is fine and working. My filter pump turned off at 3am - I looked at the spa and noticed it at 7am (so 4 hours).
In pool mode (which is what is was on last night) it sucks from pool and returns to pool with a small overflow pipe (1") to the spa (so water goes over the water fall). There is a brand new Jandy spring check valve that I installed a month ago with a new SWG (there was an old on there before i re-plumbed) and the 1" spa overflow pipe has a small check valve (I assume the original due to color being the same as all other original pipes).
the only thing I can think is:
1) that over flow check valve is broke and the higher water level of the spa is forcing water back into the pool (currently testing this theory - filled spa to overflow and now monitoring - its been 60 min and level has not moved) - so I think this is not the issue
2) Randomly something (debris) got caught in the check valve at 3am last night when the pump turned off
Has anyone had #2 happen? am I missing something else or not thinking about this right?
BTW - I am a new pool owner, its been about 6 months now and this has never happened