poo. the urchin uses its teeth to grind away algae that is on the LR. some of the LR comes with it. this is the left over calcium carbonate being excreted. every wonder how some of the sand gets created?I just noticed the sea urchin is dropping this tiny brownish/white ball things. There are probably 100 of the ball things on the ground. What would it be? The feces? Eggs?