I have several astreas. They eat any algae, diatom, or cyano but not macros or bubble. I have seen them eat green, brown, red, grey, and some clear looking algae in my tank. It doesn't matter if it is film, slime, or hair. Long, short, thick, or thin. They will eat through it. It can be on the rocks or glass. They stay away from sand though. They can't flip themselves if they get turned on their backs but, over two years I have only seen this happen once and I am the one who scared it so I turned it over right away. I wouldn't be worried about it.
If you want something that does everything above and can flip itself and goes on sand, then get cerith. They are half the size of astreas so they can get into smaller groves on the rocks. But they are smaller so they eat less in a day. They also come in dwarf size. It would probably take two ceriths to eat as much as an astrea and almost ten dwarfs to eat as much as a normal size cerith. All three of these snails do most of there work at night.
Nassarius snails eat detritus and leftover food particles. They also eat decaying matter. They do not eat algae. If you feed you fish a lot then a few of these would be good to get. Just make sure you over feed a small amount so they can get food too. If they don't have food, then they can start to become predatory.
