This is a bell siphon for an aquaponics grow bed. It fits over a 1 1/4" schedule-40 PVC standpipe. There is a helical channel in the wall that breaks the siphon. This channel is similar to the 'snorkel' that is common in bell siphons. However, I was having trouble with the siphon breaking because my inlet flow is too large. The helical tube causes a delay between the water dropping to the opening of the tube and when air enters the top of the bell. Based on 30 minutes of testing, this seems to work.
The two "lower body" are optional threaded extensions. They also extend the siphon break.
The hole in the top is to attach a 1/4" tube that I can use to break the siphon remotely. You may want to plug it.
update: added files for 3/4" standpipe