Instruct: Classify Amazon reviews into positive or negative sentiment
Query: don't order more than 1 until you are sure it is what you want

While I can't say why, the activated carbon was unusually dirty (gritty). When washing in a fine strainer it was quite dirty, and a significant amount of the volume was lost. I suppose it is possible it was end of production lot and therefore more composed of carbon dust than most. I've switched to another brand.