The thread size is a half inch (NPT). This stands for National Pipe Thread.
The instructions that come with the Berkey Biofilm Drops™ state: “It is significant to note that these levels are below the EPAs Maximum Allowed Levels (MAL) of 1.33 ppm and the World Health Organizations (WHO) of 2.0 ppm.” What do these levels refer to?
The levels refer specifically to copper. Please note that if you put fish in water treated with Berkey Biofilm Drops™, it is important to check first to see if the type of fish you have are sensitive to copper; as some fish may have a sensitivity.
Under ideal conditions, the Berkey Biofilm Drops™ have proven to remain full strength for up to 10 years. If the Berkey Biofilm Drops™ are or become frozen, the expected shelf life is half, or up to 5 years. Please note on the Berkey Biofilm Drops™ box, it is clearly stated, “Do Not Freeze.”
The Berkey Biofilm Drops™ are made up of the following ingredients: Copper Sulfate Pentahydrate – 2.5% Water – 96.5% Silver Nitrate, Complexants & Stabilizers – <1%