Abstract Laminar mixing of Newtonian and shear‐thinning fluids induced by a Hockmeyer®‐type impeller was investigated. Two unbaffled tanks at three impellers off‐bottom clearances ( c ) were studied. Six geometric combinations, i.e., two d/T and three c / T , were examined where d and T are the impeller and tank diameters, respectively. Determination of the Metzner‐Otto constant ( K s ) was undertaken. The effects of d/T, c / T , and fluid rheology on K s , power demand, pumping, shear and viscous dissipation were analyzed. The evaluated geometric ratios and rheology do not significantly affect K s and power demand, only the rheology had an impact on the remaining hydrodynamic parameters. Pumping was favored with the Newtonian fluid, and shear and viscous dissipation increased with the shear‐thinning fluid.