The tensioner is spring loaded and thus self adjusting.

See the square hole in the tensioner arm? That's for the drive lug on a 1/2" breaker bar. Insert it and use the bar as a lever to release the tension.

 

 

showoff^^^

 

Ok that was just like on my moms old buick. I really like the GM tensioner system. So much easier having a spring rather than having 8 million little bolts you had to adjust like on my old DSM.
With that being said I do have one more question. As I forgot to post yet again, it's a 1994 sls, and the belt routing looks a little different than the diagram maeng posted. I have another tensioner/idler pulley on top of the engine between the power steering pump and the alternator as in the following diagram.
http://serpentinebeltdiagrams.com/1990-1998-cadillac-seville-4-6l/

So just to make double sure. The pulley that I adjust the tension with is the one below the power steering pump, and not the one on top of the engine?

 

Your routing should look like the diagram posted above. It is a '94 with a Northstar, and not a '93 with a 4.9, right? You won't be able to move the wrong pulley, as there is only one tensioner arm, and therefore only one place to insert the 1/2 lug of a ratchet or breaker bar. And remember, you're not "adjusting" the tension, you're just releasing it to allow for removal of the belt.