Gurgling in gas tank

[Mastiff]

Noticed a fairly loud bubbling/gurgling sound in gas tank after driving today. Everything is working fine, with no other symptoms. Anyone know what the cause might be, or if it matters? This is my K5, with retrofit TBI and open vent lines (no charcoal or anything).

 

[rampage]

Return line comes in from the top. Don’t remember if it extends all the way to the bottom or not.

 

[Bent77]

You know, I've had this happen on several FI trucks.

My theory is that the pressure up against the regulator feeds backwards through the pump back into the tank. This may not be the case

 

[dyeager535]

Return line comes in from the top. Don’t remember if it extends all the way to the bottom or not.

No, just dumps in at the top. Probably more noticeable with low fuel I would imagine. Never notice it myself and I'm running a vented tank as well.