Forgive me if this has already been coverd 10000 times, but I cannot seem to keep my bell siphons from running continuously. When the siphon starts, you can see the water level drop rapidly, however, once it gets to the air holes it just gurgles and the siphon will not break.
I know this is not the issue.
1. the height of the stand pipe cap. tried caping just above the stand pipe, and have also left a 3" cap between top of stand pipe and cap. Doesnt matter.

2. the diameter of the stand pipe. I have used 1/2"PVC and 3/4" pVC. Each diameter will drain the bed faster that it is being filled.

The only thing I havent tried is to put and reducer(on inducer hower you look at it.) on the stand pipe to create the venturi effect per Annan's videos on youtube.

Suggestions?