PhycoPure(TM) Greenwater is a term for water that has green algae in it. The term and approach has been used in aquaculture for decades. Greenwater is a mesocosm technique used to raise larvae and feed rotifers. Our Greenwater is composed of Nannochloropsis algae that is great for some filter-feeders, larvae, some copepods and rotifers. It is also known to be a great water conditioner (it consumes/binds nitrate,  phosphate, heavy metals).  A bottle is good for months in the refrigerator