We have the priviledge of being the oasis for the neighborhood wasps. Their nests are not on our property so getting rid of them poses a problem. They enjoy drinking from the pool and bounce around on the lawn. They do not get annoyed when we swim or out in the yard and do not bother anything. HOWEVER, We have noticed microscopic black stuff on the surface of the pool. Thought it was settling exhaust from a train nearby, but it is only on the surface of the pool. Have never seen it before. I am guessing it is wasp Crud. Just Looking for confirmation of my theory because there is no easy remedy. Do not think it is from any pool related items. Thanks for input!