Howdy pool mavens,
I've got an odd problem I can't seem to solve.
Our spa is above the pool water level by about half. Every time the filter turns off, the spa level slowly drops until it reaches the pool water level (so it's half empty). When the filter comes back on, it fills up the spa and everything is fine.
I figure it has to be some combination of the intake/return valves on the system, but I can't seem to find the right combo. How can I crack the code?