Some Possible solutions:
- Dial-in cartridge better
- Change Phono Stage loading
- Get better phono cable
- Put spikes under table
- Better Rack
Oh, and as far as detailed cartridges, I like the ZYX. I had some Shelters before which are nice, but I think ZYX beats the Shelters at equal price points.
I'd try the cheap/free adjustments first though. It sounds like you have a decent cartridge already.