I know that a lot of gobies will sandsift (not dragonets), you'll just have to check out what kind. I think that some blennies also sand sift, but I've never had either.
Tangs will eat algae, so they're pretty good for keeping that down, but they require a lot, so you'll have to supplement their diet too. For glass cleaning inverts, go turbo snails. Don't keep them in the main tank though, almost all of those fish will eat them. There are also some snails that will sand sift, nassarius snails for example. I've used these and they're wonderful.