There are rubber flaps inside of the bypass. When inake vacuuum exceeds a certain point, it will "open" those flaps, allowing air in through the bypass. There is a fine micromesh screen there to stop any large particles, but smaller particles will still get through. It should only stay open as long as the filter is submurged in water. Once the filter can breath freely, the flaps close again, and you suck up air through the CAI again.
Leave it to Random to Needlessly complicate things.
Leave it to Random to Needlessly complicate things.
