Bayrol Shock disinfection based on active oxygen. BayroShock works quickly against bacteria, viruses, fungi, and algea. It is a very effective disinfectant in conjunction with Duo Tab, the Bayrol water treatment system based on active oxygen, but it may also be used with other active oxygen systems. BayroShock should only be used a as a shock disinfectant, it is not sufficient for water treatment alone.