So I finally got around to testing this. Modding the .STL file was too much of a pain because the resulting solid had too much going on and every click resulted in 10 minutes of computer "thinking". So I just designed a thread that matches a few different pumps I have and glued it on. In my testing at various flow rates the output seems to choose one direction and stay there rather than move around. This did cause a large vortex in the test tank but not the desired effect. I'm pretty sure there must be a deformation in my print since I did it at ludicrous speed and low print settings. I may redo it with high quality settings and see what I get.
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One observation is this "original vortex" has 4 inner fins but the VCA RFG has 5. I don't think that's the x-factor however, but more of a "I didn't copy you". Either way it's just an eductor with fins and you could experiment all day with different layouts and see what effect it has.