Help! Plumbing drain

[Shallow Planet]

So I recently modified my durso pipe to a full siphon on a dual overflow tank. 1 full siphon in each overflow and an emergency drain in the overflow. I always had the 1 full siphon but the 2nd full siphon I added is sucking a ton of air in. I see no air coming from the overflow but a ton of bubbles coming into the sump before the filter socks. In the one photo I removed the siphon pipe just to mess with it so it's not normally that short. Any ideas where the air is coming from?

Left drain with gate valve has no issues
Right drain with gate valve is the issue. Far right drain with no valve is emergency.

Any ideas are appreciated.

Thanks!

 

[CastAway]

I suppose it could be drawing in air at one of you fittings, or the valve body.

Tagging along.

 

[Shallow Planet]

Wouldn't it be leaking if air was able to come in from a fitting or valve?

 

[Shallow Planet]

Thought I'd post a follow up incase anyone else ever has this issue. Found out it was the bulkhead to my sump sucking in air. I don't glue my pvc to the sump fitting in case I want to remover for anything. Turns out enough air was being sacked in. A little plumbers putty around the edge and no more issue.