Long week so I'm just getting back to the post, love the ideas. The wire/cap is what I'll try first in the pool (not worried about getting the cal correct at this point, that can be done with software enhancements later) and well water is fairly constant requiring probably only minor seasonal adjustments. If I used a larger dia pvc pipe and put 2 loops at 180deg apart I wouldn't have to worry about gnd issues, correct? Prefer to go PIC than meter- think it would allow some data collection for seasonal level var and longterm impact of approaching suburbia on the aqua.
Switches are simple solutions for control- that's why we play with remotes, micro p's, sensors, timers etc. Most of the posters know the simple way- but what would you learn from that?- look what I've learned so far -from air pump and a pressure sensor system evolving to RCTime calc's and var caps to calibrate- awesome site