Originally posted by robvia
Could you get to much pipe and air so that the syphon wouldn't start?
Just don't submerge the outlet pipe to the bottom of the display aquarium. The air pressure in the pipe will never be greater than the water pressure at the depth the outlet pipe is at. The pressure is generated by the diffrence in water height in the surge bucket and in the siphon. As long as you have clearance above the U greater than the depth of the outlet, the surge bucket will win and burp out the excess air. The faster the pump you're using, the bigger you want to make your margin for error.