Duck dive for descent?

[Manchz]

Newly certified diver here.

Can you duck dive from surface to descend with all your gear on your back?

I recently floated up to the surface during a recreational dive (my buoyancy control not established yet), (I am very accustomed to duck diving in non scuba environments) - but found I couldn't duck dive or even swim downwards from surface as the gear kept weighing me down in the opposite direction. Was the first time I tried it, as deflation on BCD wasn't working.

 

[RGatl]

It's unfortunately easy to get in the habit of overweighting yourself to compensate for incomplete emptying of the gas bladder on your BCD. I always lean back slightly to burp the last bubble of gas in my BCD prior to exhaling and descending. Also critical to relax your body and avoid unnecessary kicking or arm movements during first 5 feet or so. I generally think about allowing my body to descend and slowly fall forward into a horizontal position. Takes a bit of practice but becomes much easier as you learn to relax in the water.