I just noticed little bugs runinng around a few of the rocks, not sure what they look like, I only saw them at night with a flash light, when the light hits the rock you can see them run and hide, there silver in color about 1/8 to 3/16 long, thin with 2 antenas sticking out by there head, and some smaller ones that are redish in color, not many of these, I don't think these are good but what are they and how do I get rid of them,