A method of making an aqueous ozone solution for an industrial cleaning system is described. The method includes providing a reaction vessel for entraining ozone gas in an aqueous solution. The reaction vessel includes a conical-shaped surface having a two or more edges or ridges. The conical-shaped surface defines an interior, and two or more edges or ridges are in contact with the interior. The reaction vessel is in fluidic communication with a supply of water. The reaction vessel is in fluidic communication with a supply of a first aqueous ozone solution. The first aqueous ozone solution is directed to the conical-shaped surface. Water is directed to the conical-shaped surface, and the water and the first aqueous ozone solution are mixed to form a second aqueous ozone solution.