In the summer I probably lose 150 gallons a day or so to evaporation with the level falling about 1/4" per day. If it falls below the skimmer level the pump will such air because the bottom drain is no longer functional. The problem is when I go out of town for work or on vacation and no one monitors the pool level.
Yesterday I replaced the manual fill valve with a 24VAC valve and hooked it to my sprinkler controller so I can add water automatically, but there is no feedback as to the water level. I'm trying different daily fill times to find one that maintains the water level relatively constant, but it's inexact and depends on the weather.
I want to construct some sort of level detector that will cut off the automatic fill valve if the level gets too high, or I could disconnect the timer and hook the level detector relay directly to the valve.
I was thinking of this:
In the winter and spring I often have the opposite problem, the pool overflows from rain, and I'd like to also do something that opens the pump's drain valve diverter and removes water until the level falls to the proper level.