Kephra, today I tested various concentrations of hydrogen peroxide and 1ml/liter resulted in no visible change in colloidal silver. To lighten it, 5ml was needed, and to be very transparent, 10ml/liter was needed. As it is only for external use, is there any problem using this concentration of hydrogen peroxide? It is worth mentioning that I did the test on only 50ml of colloidal silver, using the proportions. I will attach a photo showing how it was before and how it was after in the small measuring cup.