Cuc for hob refugium

[Marchillo]

i have about a 3.5 gallon Hob refugium I run cheato in. What would be good to put in there to maybe stir up sand and/or clean up the algae without devouring the cheato. It also has 5 pounds of sand.

Thanks - I'm thinking like 1/2 small snails or crabs. Whatever works best.