My sand burped!!

hhmmm! I would say like a bubble every 15 to 20 seconds, funny that area is the only area this gas escapes.

 

Having a shallow sandbed keeps that from happening.
Especially good if you have LR and macro algae to boot.

There are advantages to DSB's, disadvantages too.

 

It could be several things. It could be trapped air from adding the sand (especially if it is only 2 mos. old), N2, H2S, or even O2. The latter is actually very common with healthy sandbeds that contain cyanobacterial colonies, which can and do produce visible bubbles of oxygen. It can stream pretty rapidly from beneath the surface under ideal conditions.