If my outlet is low enough for the siphon to work, then it should keep right on siphoning until air gets in somewhere, right?
Air will stop it, trying to lift the water over 34 feet will stop it, the highest point of the outlet being less than required drop below the pond's water level will stop it.
In my old pond, the pool side of my dam was dug out 10 feet below the grade level of the dry side, so I had to run pipe several hundred feet down a slight slope and into a creek bed to get the required outlet drop.
