The 3-D visualization of passive tracer mixing inside a stirred vessel offers a powerful means of validating computational models. Taken together, the forward elevation and underneath plan views (acquired by a 45 degrees mirror) of the mixing of a visible tracer in space and time, captured on video, present approximately 0.1 Mb of data per video frame. This density of potentially quantitative concentration field information is very suitable for validation of computational fluid mixing (CFM) predictions for models comprised of the order of 10(5) voxels. New results are presented for an axial pumping 45 degrees inclined-blade turbine in a semi-tech 30 dm(3) vessel equipped for 3-D visualization. Passive scalar mixing tests have been evaluated using an improved networks-of-zones model with 32,000 zones. Conformal stretching of the radial flow configuration of existing software provides a simple way of accommodating the predominantly axial flow pattern. Good agreement between theory and experiment has been demonstrated using AVS graphics, giving see-through close to photo-realism reconciliation of mixing images for two different injection positions.