Can we use chlorine dioxide to prevent diseases?
Chlorine dioxide is an oxidising agent. Its mechanism is to attack all forms of organic matter (that is, carbon-based material—as in ‘organic chemistry’. Not ‘organic’ as in ‘pesticide free’ etc., produce).
An oxidising agent is not selective as to what it attacks and hence it will destroy all organic matter such as dead roots, bacteria, fungi and otherwise healthy live roots. If the level of oxidising agent is made high enough to ensure a kill of disease bacteria and fungi, it will also be high enough to kill the plants in the system.
Common oxidising agents possibly used with hydroponic solutions are chlorine dioxide, chlorine, calcium hypochlorite (granular pool chlorine), sodium hypochlorite (liquid pool chlorine—especially not recommended), ozone, and hydrogen peroxide. There are other chemicals such as copper and iodine, which are not oxidising agents, but have the same impact.
Continuously adding an oxidising agent to a water-based system results in all plant roots in the system being exposed to damage. In practice, levels as low as only 1 ppm (part per million) have sometimes caused damage.
Read more at Practical Hydroponics & Greenhouses