Sub Sonics and woofer pumping

I have a VPI prime on bear claws sitting on a maple base. Floor is concrete. I use a Nagaoka MP500 cart with going to an ARC PH3se phono pre, then to a Herron 1A preamp. Amp is an ARC Classic 60. Speakers are Thiel CS 2.4’s. 
I get pretty aggressive woofer pumping with vinyl. 
I’ve lubed my bearings on the table.

my alignment is spot on. 
Tracking force at the upper limits of cart. 
I’ve added the 2nd pivot point to the 3D arm. 
I’ve even switched out the counter wt to a much heavier unit and added a comparable head shell weight to change the total mass of arm. To no avail. 
None of these things have had any effect in reducing the pumping. 
I REALLY don’t want to use a rumble filter. 
I’m left with the conclusion that the cart may not be a match for the arm, even after adding all the extra mass. 

Any thoughts or solutions.