I have patches of brown algae on my sand bed.
And I've been told by a couple experienced hobbyists to get a couple sand sifting starfish, which would help in turning over the sand.
I was also told that they definitely eat the fauna in sand beds, but many argue that their consumption rate...
I cut them as close to the base as possible and then stick a toothpick through the cap for use as an anchor. Now you can slide the toothpick in a hole or crevace in your LR, or you have the option of gluing it as well.
