missing the point
your question is what would do bottom scraps and algae well, and my answer is "none". Shrimp will eat scraps, snails will do OK on algae, but there's not much out there that does double duty and does it well.
My kuhli & shrimp are good scrap clean up crew, and the snails & hillstream handle the algae (LOL I have one large clean up crew that only has five "non-cleaner" animals).