The model fitted the experimental data satisfyingly in the various geometries and configurations, and the tracer data were especially well reproduced in the bottom parts of the multi-impeller vessels. This comes as no surprise, as a cascade of ideal stirred tanks connected by exchange flows -a discretization of the dispersion model -can replicate experimental tracer curves and has been used in multi-impeller mixing time correlations as well . In the single-impeller configurations (panel D in Figure ) the oscillations of the tracer signals could not be represented by the dispersion model, but the exponential approach towards a perfectly mixed state, the most important feature, was captured. These results suggest that the dispersion model describes mixing most accurately in tanks with multiple impellers.