From what I have read it is best not to stir it. In my first attempt I mixed Southdown with my established CC bed and had little luck producing the DSB effect. Further reading leads me to believe that this is due to the CC being sharp and is an irritant to many of the small critters that populate a true DSB. I added sand sifting stars and cucs to this tank and in about 4 weeks it just took off, never looked better, but still not much activity in the sand.
So I figured I better try it again (darn, I had to set up yet another tank, tee hee)I have a 65 gal. reef with 8 inches of Southdown, ten pounds of LS from a friends tank and 100 lbs of live rock from various established tanks, circulation only and 192 watts VHO PCs. I introduced nothing to disturb the sand but did add a good number of snails and hermits from my other tanks and it cycled in less than 4 weeks. I never do water changes on it and the sand is amazing. Technicolor! I am very pleased with this tank and my softies do excellent in it.