Page "Buoyancy compensator (diving)" Paragraph 38

With experience, divers learn to minimize this problem, starting by minimizing the size of the " constant volume bubble " in their BC's.

This requires learning the minimum weighting requirement needed for their system ( see factors above ).

These techniques keep the volume of the gas bubble within the BC as small as possible at the beginning of a dive, while leaving just enough gas in the BC at first submersion to be able to compensate for the expected slow loss of diver weight as the dive progresses, as a result of gas used ( in practice, about 5 to 8 lbs.

lost per cylinder, as noted above ).