I have a area of the yard that has gravel, that the dogs have been trained to use. The problem is cleaning it. I have used bleach in the past and found the smell has come back after a week.

Is there some industrial strengh "something" that I can use. I know they sell odor eliminator, but only in little containers. I need something that will treat a 8 X 8 area.
Also where would I buy it? I live in Manitoba Canada.
you may want to try lime and water it in really well