I get more vorticies with the closed loop on the four way because of the variations in force that occur when the drum moves between the outlets. The water force does change as this happens as well. The pulling force also adds a negative force so I get a push pull effect near the bottom of the tank.

The vortecs do that too but because the intake on CL is so much bigger it draws in water from a larger area. I also have two intakes for two loops.