A device having: a chamber having a gas inlet, a gas vent, and a liquid vent; and a float and a weight coupled to the chamber. The float has a lower density than the chamber. The weight has a higher density than the chamber. The aggregate density of the chamber, the float, and the weight is greater than the density of the chamber. The gas inlet, the gas vent, the liquid vent, the float, and the weight are positioned on the chamber such that: when the chamber is filled with and submerged in a liquid in which the chamber is neutrally-buoyant, the chamber is oriented to place the gas vent below the gas inlet; and when a gas is introduced through the gas inlet into the chamber that is filled with the liquid, the chamber pivots to raise the gas vent until a portion of the gas escapes from the chamber through only the gas vent.