Today, I picked up 12lbs of worm castings from the hydro shop, for $.50lb. I thought that was a screaming deal, until I got them home an examined them. It looks like nothing more than semi-screened dirt, or manure. I already called the hydro store back, and will get a refund if I want. The castings I've always bought before, looked like dark coffee, tiny bead like grain. More expensive, too. What quality are these $.50lb castings?