I just got off the phone with a customer, who asked a great question. Our Fruit and Vegetable Purifier generates both Hydroxil Radicals (when only water only is added), as well as Hypochlorous Acid (when salt and vinegar are added). While we have outlined how to test for HOCl, there is no test strip or digital meter available on the market that tests for Hydroxil Radicals, so how can one be sure that the machine actually generates them.
Although Hydroxil Radicals can not be tested through any commercially available test, they can be tested with Methylene Blue. Methylene Blue maybe familiar to many who have aquariums (it is commonly used as medication for fish). It is an extremely powerful die, and when used in fish medications, is often accompanied with a warning that using it can stain the aquarium.
Like many substances, Hydroxil Ion will attack Methylene Blue on a molecular level, causing removing the blue color from the solution. If you want to test this, you can add Methylene Blue to water until it is noticeable, then add it to the fruit and vegetable purifier, and run the cycle. The blue color will dissipate.