K. Version #2. I don't know that much about electric, so I don't know exactly how it'd work, but the electrician that one of my clients uses says that he could rig it to work.

In ditches, he uses 2 bare wires. When the water gets high enough to cover both wires, a pump is turned on to pump down the ditch. He said that he could rig up the same system, but just in reverse to shut the well off when the 2nd wire touches the water. I have no idea what voltage is involved in this set-up.

How to configure the pipe from the well so it doesn't freeze is the question. Maybe open end, and a slope so it is self draining into the pond once the power is turned off? Make sure that the whole pipe is below the frost line.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).