Gator,

I should have said that once the siphon starts it will suck the water out of the 4" pipe faster than the hole(s) can can allow it to enter, thus allowing air to break the seal stopping the siphon.

You could quickly make a miniture "model" out of 1/2" or 3/4" PVC with the same basic design and put it in a tub or bowl of water and see if there is a problem.

Good luck.

Dan

Mistakes are proof that you are trying.


Dan