My 125 gal has a layer of potting soil mixed with a little sand, topped with regular black aquarium gravel. The plants don't seem to thrive, but the hardy ones do great. I've posted some photos in the gallery if you want to look. I've never had issues - even when I've had to replant or move things around. My pleco (he's a16 or so inches long) kicked up a huge cloud one time - made a massive mess on one end. Caused NO problems with the tank at all (which surprised me). Think clouds of dirt like when you go swimming and kick up the dirt. I didn't lose any stock - snails, shrimp, tetras, yoyos, kuhlis, etc - big community.
Hope that helps!