Bean Animal problem

[Dorado]

I'm starting a 150g tank and after turning the pump on, the primary drain in the overflow doesn't seem to me draining. The water raises up past the primary and the secondary starts sucking in air through the air gap. When I turn the pump off, the water only drains to the bottom of the secondary and the primary is still under 2" of water and not draining at all. I just thought that a siphon would start automatically. The valves are all wide open. Do i need to drill a hole in the primary as well? Any help would be great.

A visual of my setup

 

[dbowman5]

I'm starting a 150g tank and after turning the pump on, the primary drain in the overflow doesn't seem to me draining. The water raises up past the primary and the secondary starts sucking in air through the air gap. When I turn the pump off, the water only drains to the bottom of the secondary and the primary is still under 2" of water and not draining at all. I just thought that a siphon would start automatically. The valves are all wide open. Do i need to drill a hole in the primary as well? Any help would be great.

A visual of my setup

the primary should not have a 90 90 on top if it is in water at the bottom. This causes an air lock. when there is a HOB they put an airline into the overhang (top of the hose) to allow air to escape while the siphon is establishing then pull it out or put it under water to seal it. i think that is what is happening. i use a Bean and i just have a strainer in the bottom of my overflow box and the full siphon starts every time

 

[ca1ore]

Assuming there is no physical blockage, agree that the primary is getting airlocked. This happens with a ventless U in the overflow box and when the outlet in the sump is submerged. either drill a small vent hole in the U or get rid of it.