Phono Hum w/ Pro-Ject Debut III

I am experiencing phono hum with my Debut III. Phono leads are going into my phono inputs in my Sunfire Theater Grand II. I think I am getting AC feedback from cable routing in the back of the system. The ground wire is connected from the TT to the Sunfire. I started moving the phono leads away from the AC lines and the hum has lessened but it is still there. Is there a good way (material) to shield the phono leads without changing out the leads themselves?