Spa drains into pool when pump turns off - have changed check valves

[oropeza]

Our swimming pool is several years old and every night the raised spa drains into the swimming pool once the pump which circulates water is turned off. We did some research and were advised it was likely a bad check valve, so we replaced the two check valves in first picture (switch is between the spa and cleaner). The spa continued to drain and so found another post advising a check valve should be installed before the pool pump, and so installed that as well (2nd photo), however, the spa continues to drain to just below the level of seats in the jacuzzi. Our pool is approx. 45 feet long and jacuzzi is at far end away from the pump so don't know if the distance between that and the check valves would have some bearing. We are out of ideas to try. Below are some photos of pool equipment and the spa

 

[Jimrahbe]

O,

How far down does the water drain? Does it stop right below the jets or does it drain down to the floor?

I assume your in-floor-system (You have my condolences, btw.. ) has some pop ups in the spa???

Thanks,

Jim R.

 

[Dodger]

That looks like a Caretaker in-floor valve in your second third picture. If yes, then the one port that goes down from that Caretaker to the spa zone should have a check valve on it. Mine is a smaller Ortega check valve that juts out at 90 degrees, not the same style as the check valve you have on the return lines in the 1st picture. Below that Caretaker dome, your spa water could be draining back through a faulty (Ortega) check valve and into the pool through the 4 pool ports.

Of course, one problem is that Ortega check valves are not marketed anymore and I'm not sure if you can replace like for like.

(Edited for clarity.)