gully washer,
Thanks for posting the links. I have seen the drawing and the main difference in this system is that I wanted there to be a design that anyone could use no matter where they were located. I want this system to work from Florida to Alaska. The drawing you linked has a potential problem with trash (debris or bees nest) blocking the vent and being broken when mowing especially in southern climates. In northern climates you potentially have those same issues along with an ice block in the vent pipe. If the vent were blocked in either circumstance the pond could completely siphon. You are correct the concern I have being the extra length of pipe between the tee and the cap (I will call this part the riser) in starting the automatic siphon. Frost lines vary throughout our country. In areas there is no frost line and in others it may be as deep as 6 feet or more. This is why I initially asked about a check valve. If there were an issue with the riser (which you don’t think there will be), can an air bleed be installed underground on the riser and not have a problem with manually starting the siphon? I’m just trying to find a solution for everyone who wants to use a bottom withdrawal siphon system. I figured with all the knowledge on the Pond Boss Forum we can find an answer.
Thanks!
Heppy
