The use of water as a dispersing liquid for particle size analysis can often result in misleading or even incorrect data due to air bubbles that may be present in solution. If the air bubbles are not removed, the particle size analyzer may see them, and they may be incorrectly reported in the measured distribution. The AquaPrep operates by recirculating water through a hydrophobic capsule consisting of many thin-walled capillaries. A vacuum pump in turn provides suction on the outside of the capillaries. This results in a diffusion of dissolved air from the water through the capillary walls and into the vacuum pump.