Hmmm... Just dawned on me there may be a very cheap and effective solution: since the flow from the pit is gravity fed and the flow rate can be set with a valve, why not calculate the time it takes to drain the pit to a determined low level? Then use that time interval to set a timer to turn on the pump when that time interval is passed? And also set the timer to turn the well back off at the full mark of the pit?
Thoughts?
Hey Phil (JKB) I know you're peeking and rolling your eyes!