I _think_ one drop is equivalent to 1mL but you should check this by measuring number of water drops into a measuring cup...Argenteus said:The intruction says to use 5 mL per 50 gallons of water. How many drops or mL is that per 1 US gallon?
Good to know...konrad05 said:1 drop of liquid is equal to 0.5 mL. Therefore 1 mL treats 10 gallons and one drop treats 5 gallons B)