Hey there, I have a 13.5g tank I've had running for around 4 months now, and I have recently had some problems with a thick, brown algae that has begun covering the walls and sand of my tank. Its easy enough to scrape off the walls with a razorblade once a week when I do my water change, but I don't know what to do about it on the sand. my 2 blue legged hermits and 2 emerald crabs don't seem to touch it, so I was wondering what kind of cleaner invert I could add who would deal with the sand algae, or at least move the sand around enough that it cant reform. I currently have it stocked with a small six-line wrasse, the two hermits and emeralds, a feather duster, a soft leather coral and a mini carpet anemone. Any help would be appreciated!