My previous understanding was that a siphon system that never loses suction will run wide-open until the level of the pond drops to where the vent tube sucks air? Now, I am hearing a siphon system will only release water at the level it is entering the pond.......not sure how this thing works, but for whatever reasons, my Wife and I were not able to create a siphon so I assumed we had a blockage.
Most of the time ... the siphon is not siphoning. It just acts like a culvert. This is because most of the time there isn't enough water flowing into the pond to fully cover the siphon. When the water level rises above the highest point of the siphon (the highest elevation INSIDE the siphon) things begin to change. There is pressure that can fill the siphon fully and purge the air. At some pond level above the apex of the siphon ... a point of no return will take place ... and the siphon will purge the air (or at least most of it) and will develop a suction on the pond side that will lift water. Once activated by high water... it will roar ... provided your inlet is not obstructed.
