# Generating hypochlorous acid for disinfecting water using HClO2

I use a product that contains $$\pu{700 ppm}$$ of $$\ce{HClO}$$ to disinfect water at $$\pu{1 ml}$$ per $$\pu{1 l}$$ and let it rest for about $$\pu{2 hrs}$$ before I use it so there is no $$\ce{HClO}$$ left because I will mix it with enzymes and rhizobacteria which could be destroyed by the $$\ce{HClO}$$.

I found a device (Eco One Electrolyzed Water System) that can generate $$\ce{HClO}$$ at $$\pu{200 ppm}$$ using just water and $$\ce{NaCl}$$ at a $$\mathrm{pH}$$ of $$5$$, which would be much cheaper in the long run.

Will this have the same disinfectant effect when I add $$\pu{3.5ml}$$ per $$\pu{1 l}$$ water of the $$\pu{200 ppm}$$ solution and should I also let it rest for $$\pu{2 hrs}$$?

In a closed container such as a spray bottle, the concentration of hypochlorous acid decreases about $$1\%$$ per day.

Are there any buffers or stabilizers that I can add to the generated $$\ce{HClO}$$ to slow down this process which are safe and environmentally friendly when the water is used for watering fruit plants?

• Why not to use the commercial stock solution of NaClO ? As HClO solution would contain NaCl as well. – Poutnik Aug 27 '20 at 13:08
• Looks like that NaClO is not that easily available in my region, but I found that I could buy NaClO2 25% (which is also used for water treatment in my region), would this be safe to use? I also thought about using H2O2, but I could not find any information how long it takes for the H2O2 to disintegrate. Most important to me is that it will not leave any toxic substances in the water and that I can add enzymes and rhizobacteria after a fixed amount of time (e.g. 2 hours like for HClO) so that they get not destroyed and to remove most of bacteria / spores. – tbraun89 Aug 27 '20 at 13:55
• I have never thought that the "liquid bleech" can be not easily available, unless shops are empty because of coronavirus. Chlorites will be more stable than hypochlorites. – Poutnik Aug 27 '20 at 13:57
• I only found products that also contain other chemical like Na2CO3 for private customers and found reports that it's not safe to use it with plants, but I'm no expert in (bio)chemistry. I found some chemical suppliers which don't list NaClO right now, maybe because of coronavirus. – tbraun89 Aug 27 '20 at 14:06
• Like poisons, all is matter of dosage. Na2CO3 dosage comparable with the active chlorine dosage is harmless. Eatable pretzels are being soaked in NaOH to get nice dark brown and shiny crust. – Poutnik Aug 27 '20 at 14:10