At one wash we mix it in small 5 gallon batches in a 15 gallon container. If you mix it in a 55 gallon drum it's easier to mix it in the 55 gallon drum if you use a barrel mixer. Add about 20 gallons of hot water, then start adding the Correct as your filling the drum with the mixer running. Wear a mask while your adding the Correct, it can get dusty.