if you order the same tub size rack (say a CB-70 enclosed rack, and a CB-70 economy rack) yes they would stack. but different size tubs/rack/tub brands may or may not stack
Vision makes some tubs that are standard sizes, like the V-70 tub. this is the exact same size as the IRIS CB-70 tub, so it will fit.
AP lists the tub dimensions for each rack on the individual rack pages. So all you have to to is compare the tub dimensions given by AP with the tub dimensions of the vision tubs to see if they will fit.