Operating conditions (impeller speed and power requirement) to 'just draw down' light particles in a stirred tank were determined. The effects of impeller type, submergence and number of baffles were investigated. Visual observations revealed two mechanisms of draw down; through recirculation loops and through vortices. The latter occurred mainly when the; nun fiber of baffles decreased from the standard 4 to 2 or 1, and/or when the impeller was mounted close to the liquid surface. Choosing a high impeller submergence in a fully baffled vessel ensured a more stable operation as torque and flow instabilities due to vortex formation were avoided. This configuration was also found to be more energy efficient. Additionally, it can be advantageous when gas/vapour entrainment from the headspace is undesirable and allows varying liquid level over a larger range in industrial practice. An axial or a mixed flow downward pumping impeller required less power but higher speeds to draw down compared to a radial one.