Crabs, snails, serpent or brittle stars. Sand shifters won't accept this kind of substrate, they prefer fine sand of 0.5-1.0 mm grain size. Conch snails might accept abit bigger.than that. Vacuuming, and small frequent water changes also a must in this case. Biweekly waterchanges could be a result of big amount of detritus below the substrate, and if stays there it will break down to nitrates...High nirates levels are the main source of unexcepted late algae blooms.

IMO fine sand bed is more attractive, and much easier to maintance. Mine is still snow white, and I never stir it before.