Spa emptied to pool level last night

[Wicked]

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

 

[Bama Rambler]

It was surely a stuck check valve. It isn't all that uncommon for something to get stuck in them temporarily, or they just stick temporarily. If it does it on a regular basis or constantly you'll have to do some further inspection of them.

 

[Wicked]

It was surely a stuck check valve. It isn't all that uncommon for something to get stuck in them temporarily, or they just stick temporarily. If it does it on a regular basis or constantly you'll have to do some further inspection of them.

Thanks! Its now been over 4 hours and not a drop in level so I have to agree with the stuck valve. I just hate when things happen mysteriously and then never happen again - I like to know why

Bummer - when I re-plumbed in my new SWG and pump I almost replaced that valve since I was right there in the area doing work. Hopefully a fluke and I dont need to re-plumb more

 

[Wicked]

Just an update. It's was still draining intermittently. So I decided to replace the spa I overflow valve yesterday with a clear spear unit. I also used unions for ease of future replacement.