cheap clean up crew

[Proteus]

You need a variety IMO. Some say no crabs even emeralds and hermits. But I use both.
As for snails. Nassarius,cerith,asterias are great. Turbos are good but are bull dozers.
Also any snail that's pyrimid shape can have trouble flipping themselves upright and will die without your helping hand. Adding nutrients to tank

A conch and urchin are also benifical.

With the urchin they are herbivores so once algea is gone they should be supplemented with nori. If it starts loosing spines you know it's not doing to good.