Herbie style overflow

[fkshiu]

You don't really have a "classic" Herbie overflow. I agree it's more like Bean's which is really just a modified Durso with an emergency drain.

A Herbie has drains on the bottom of the overflow box so the water can only flow one way: down. There is no air introduced into the system.

sphelps's solution should work, but you'll basically have a Durso which is a controlled way of introducing air into a drainage system.

Here's my Herbie: