Most critters that "turn over your substrate" also deplete it of beneficial microfauna, and when this happens, if the critter in question isn't weaned onto prepared foods, it starves.
I would, however consider about 4 large Nassarius snails (the nice big Tongan variety are best), as they live in the substrate and pop out to eat carrion, leftover food, feces, and detritus.
Cerith snails also live in the substrate, and will actually eat algae off the glass just below the sandline.
Peppermint shrimp will eat small appies, as well as algae and leftovers. You could add a up to four in a 46 gal.