If you "must" have a sandsifter, be aware that the available substrate area won't support one for very long at all (when they "sift", they're actually stripping the substrate of microfauna). SO, be sure to get one that is eating prepared foods, or be ready to wean the fish onto prepared foods or the fish will starve.
Some folks bury small "piles" of mysis or other foods in the substrate for them to sift out, however, one needs to be sure they are eaten, lest they trash the water quality.
HTH