Hey philly,

Getting a bad tracking percentage reading indicates that SSL isn't receiving a strong signal from your turntables or your picking up interference.
I would first verify that your turntables are grounded.
If they are I would next look at your scopes and verify that your seeing solid circles.
If your circles are really fuzzy it could mean your needles are dirty or worn out or your vinyl is worn out.
Swapping needles or vinyl at that point could fix it.
If you see a straight line in the scope then SSL is only receiving half of the left/right signal.
This could be due to a short in the wiring on the needle, a bad connection between the cartridge and the tone arm, or a short in the rca coming from the turntable.
You could try changing cartridges, cleaning the contact points between the cartridge and tone arm, or jiggling the rca coming from the turntable.
One of those will hopefully bring back the good signal.

As for interference.. you need to calibrate your setup.
To properly calibrate, play music as loud as your going to be playing throughout your set.
Put the needle on the turntable with the platter stopped and hold down the estimate tab for about 5 seconds.
This should automatically set the threshold to where it needs to be depending on the environment that your in.

When your in your bed room playing on a smaller sound system you should get a lower threshold setting although when your at the club playing on a large system the threshold will typically jump to -24.

The most important thing to look at is the number in the upper right corner of the scope view while the needle is on the record and your platter is stopped.
If this number is fluctuating then your going to be picking up interference.
You can also adjust the threshold manually by simply dragging it to the left while looking at the number in the upper right corner.
You'll know you've gone too far to the left when that number starts to fluctuate.
At that point, drag it one notch to the right.
That is the perfect threshold setting for the environment that your in.

Hope some of this info helps:)