Jersey, my pond builder originally installed a 45 degree elbow on my steep discharge pipe (6"). He gave me another 45 elbow and about 4 feet of pipe. He suggested that I use a short piece of pipe to connect the second 45 and then try adding about 3 feet of pipe to the new elbow so that the outlet is significantly higher. If that automatically starts the siphon I can experiment with cutting the final piece shorter.
How big is your pond? Once the siphon started I could tell that one 6" pipe is plenty for my little pond.
