This pool was leaking at the equipment pad (pump housing was cracked & filter backwash valve had leaks at the fittings).
The spa is also 4′ above the pool and would drain down to the spa jets every night when the pump was off. I replaced the check valves & valve diverters but spa still drained into the pool at night. This led me to believe one of the valves isolated to the spa was warped.
#1. Replaced the old pump with a new Pentair high head Challenger 2h.p.
#2. Replaced the backwash valve
#3. Replumbed equipment pad and replaced all valves and check valves.
Spa retained it’s level overnight and no leaks at the equipment pad. Also I was able to minimize fittings in a couple places reducing overall friction loss.