first, how old is the tank? your thing says new nano tank, so i'm guessing it hasnt been set up for very long? If its new, its perfectly common to have excess algae all over.
Second, what are your nitrates and phosphates? It is very important to keep those down as low as possible to keep algae from growing.
Last thing, what type of snails do you have? Crabs arent gonna do anything for the sand really (specially hermits) but you should get a few ceriths snails for sure, and maybe some nassarius too. The nassarius wont eat any of the algae on the sand, they just burrow in it and can help stir it up a bit. The ceriths will actually dig in it and eat the algae.
