Hydrogen peroxide works very well against any pathogens, and chemically turns into water and oxygen after exerting its sterilizing effect. This is very convenient for the grower as there is no toxic substance potentially contaminating the plants or the growing medium. You can spray it all around the grow room, and also use it on a rag to sterilize reservoirs, cloning devices, fans, lights, all the components of hydroponic systems, and any other potentially contaminated place or device.
After a deep cleaning, a sterilization practice at the end of every harvest with bleach or hydrogen peroxide is a good insurance no pathogens will proliferate when you start the next crop. Always remember that both bleach and hydrogen peroxide can cause chemical burns. When you use a chemical sterilizer it is always a good idea to protect your lungs and your skin, wearing gloves, masks and goggles.