Rega RB300 Anti-skating problem

I have a Rega RB300 tonearm and a Grado Master Reference cartridge ,
currently the VTF is 1.6 grams and the anti-skating is set to zero .
When using Cardas records that have blank tracks the tone arm wants to move to the outer edge of the track .
This is with the anti-skating is set to zero ! if I set it to anything above it moves outward even faster .
The only way I can have the cartridge not move on the blank tracks is to set the VTF to at least 2 grams .
Checked tt ( Merrill Heirloom ) level , Checked plater level ,
the only thing I can think of is the anti-skate magnet is not working as intended ( the tonearm was re-wired ) .
Any thoughts or suggestions ?

Thank You All
I think that maybe that answer is that for some reason 
the anti-skating is somehow preloaded to 2 grams at the zero setting .
Why else would it move away from the spindle with a VTF of 1.6 grams 
and stay stable at 2 grams .

I thought about the magnet being reversed , when I look at the parts breakdown of the Rega tonearm I don't think it could be , even by mistake .
I use a one sided record to adjust anti-skating. Take a look at this video!
OK vair68. With anti skate set correctly the arm will always move to the outside on a blank disc because there is twice as much friction in the groove as there is on a blank disc. In the groove the stylus is contacting the groove at 2 points. On a blank disc only one. With a line contact stylus this discrepancy is even worse. The correct way to set anti skating is with a test disc like the Hi Fi News disc which has excellent anti skating tracks. Too much anti skate and you get distortion in the Lt channel to little and you get distortion in the right channel. You adjust it until you get no distortion in either channel. If you can get this increase the tracking force a little. There are other must have tests on the record. Do it right. get the disc!
Thank You All 

Today I checked the level of the TT, the level of the sub-chassie  ,
the springs and counter weight , re-adjusted the cartridge offset , re-aligned the cartridge , played with the weight using the Rega VTF vs. just the counter weight ( settled on 1.65 grams ) .
The arm still moves outward slowly on a blank track ,
but right now the sound is fantastic .

I wanted to contact Rega but they refer you to local distributors/dealers ,
The Sound Organization Rega's U.S. distributor e-mailed me back ,
I will call them tomorrow and let keep everybody updated .

If the cartridge is new...give it time.  If you can adjust rear of the arm higher to give more snap.  I wouldn't worry about a/s. Don't adjust a/s with a blank record....never right.  If you're happy with the sound just play records