Static mixers are widely used for fluid blending operations but few independent data regarding their performance in the turbulent regime are available in the open literature. Extensive blending data were collected for the Sulzer SMV and Chemineer KM and HEV mixers in the transitional and turbulent flow regimes, using a laser-induced fluorescence (LIF) technique. The data collected indicate that the mixture quality (CoV) produced by a unit is independent of the flowrate ratio of the main:added streams. This contradicts the correlations produced by the manufacturers. (c) 2004 Elsevier Ltd. All rights reserved.