Re-read what I've written and yeah. I used incorrect English terms. Since water in this amount, and the forces that work on it, we can relate to it as steady flow of an ideal, non-compressionable, liquid (I hope thats more correct), and while you are right about amplify and hinder, there is the possibility for the water to not rotate at all, if we look on the gravity-coriolis comparison, it would do movement as such you can see in this thing old clocks have which escapes my mind. Harmonic.
I don't mean to disprove here the fact there is rotation, just the fact that it is caused by Coriolis acceleration, rather than geometrical reasons. And the misbelief that it has a predetermined cycling side.
The numbers I've show are very relevant, since they show how insignificant Coriolis acceleration is in the system. Even a nearly perfect plumber would do the job with a deviation degree of ~5 degrees. That just shows how insignificant Coriolis acceleration is, when you have gravity that plays in.
EDIT: Not to mention the fact that if you look at local geometry, a simple local field tolerance that at a sink would be like, what? +-0.5 mm? That alone would yield a local deviation that is creating a force far bigger than Coriolis. What I've shown is just Geometry vs spinning systems derived forces