Gunter

Tinkerer!! 

Help! 

Gunter is in need of refueling. Help him Choose from the 9 tanks in front of you. These tanks contain either water, potion, acid, or gasoline. Each liquid reacts with the same or another type of liquid. You must mix two liquids at a time and deduce which tank contains the gasoline. 

Remember, you only have 9 tries until the valve Clogs up. Hurry!!!