Pods will be in the sand along with many different micro organisims that YES the sand sifter will deplete. Over time you'll probably need to add sand to keep the fish fed unless you can get it to eat prepared foods.
It took me 11 months to get a white sand bed. You just have to keep up with water changes, have adequate flow, and a balanced clean up crew. No need for a sand sifting fish IMO. If your rocks aren't secured or are on the sand, sand sifters can dig around the base of the rocks and cause an avalanche.