I have been operating on the assumption that if it siphons for several hours or days and then stops, it must be getting air in it somewhere. Whenever I go to restart it, there is never any evidence of a clog. On attempt 6 or 8 I slid my last section of 2" PVC (at the inlet) into a ten-foot section of 4" corrugated pipe. I am hoping that will deter a vortex.

If my outlet is low enough for the siphon to work, then it should keep right on siphoning until air gets in somewhere, right?

“That boy, I say, that boy's about as sharp as a bowling ball”