Well myself and many others who i have talked to and meet have all had issues with Sand.. Its amazing stuff, looks great, but does cause issues.. Now again, i was talking from personal expereince.. and my current tank witch is larger tank than most, and i have larger fish, i currently have a large Naso tang, who when i was running my tank with "southdown Playsand" would go and Race and kick up soo much sand that in fact i replaced the prepeller in my Powerhead 402 3 times in 1 year.. every time i took the unit apart it was the sand particals in there..
As for the DSB, i currently no longer use Southdown, had issues with it.. and i have a very well and active DSB using just plain old Crushed Coral... and when stated about syphoning the crap on top of the substrate i was talking Brand new sand.. you just dump it in, wait a couple of days the for the cloudy ness to clear the run your syphone overtop about 3-4 inches above the substrate.. to get off the powdery residue.
but we have straied of topic here..
the Question here was , that he knows that Sand"Can Cause damage" no one said it will but it can cause the damage, some have been lucky, some have not.. but he asked if Powerheads and Canester filters use the empellers.. witch yes.. 99% do, if not all of them.