New over flow box, is this correct?

[plc001]

Quick question, does this look correct to you? Brand new overflow, trying a Ken Stockman's Standpipe but about every 45 sec I get a gurgling sound:

 

[Saltyreef]

Quick question, does this look correct to you? Brand new overflow, trying a Ken Stockman's Standpipe but about every 45 sec I get a gurgling sound:

Airs being trapped somewhere. This unfortunately is really the best it gets with a single drain.
Even my lifereef silencer is loud still.

 

[huckilt]

I run an eshopps single drain overflow and as long as you tune it jus right you can get it almost silent. You jus gotta make sure there’s no air bubble trapped at the top of the u pipe and use a valve of some sort to control the flow and get a perfect syphon. Mine uses a normal standpipe with slots and a foam filter over it though.

 

[theMeat]

Fashion a stockman standpipe. Oops, see that’s what you got. That’s about the quietest you can get once tuned. A valve or adjustment on the air hose coming off the top is needed to adjust. Can’t tell from pic if you have one