The only technique I can find listed is running copper wiring into the tank &gt;and attaching it to a six-volt battery for a few hours, which probably &gt;causes copper to form a solution in the tank (technique Dr. Andrews uses).
(a solution in the tank; uses; Dr. Andrews) (a few hours; probably causes; copper to form a solution in the tank) Context(a few hours probably causes,List([123, 161))):(copper; to form; a solution in the tank (technique Dr. Andrews uses)
a few hours probably causes,List([123, 161))
a solution in the tank a few hours copper
uses probably causes to form
Dr. Andrews
copper to form a solution in the tank
a solution in the tank (technique Dr. Andrews uses