Hi. My name is Tracy Presnell and my wife and I own 3R Odor-Con/Purogene Sales and we are the North American/Canadian distributors of Purogene. Dave sent me the text of this post and I requested that he allow me to respond to it since we are the "factory" when it comes to Purogene for RVs and Boats.
You do have some things right. Sodium Chlorite is a precursor for the production of Chlorine Dioxide but Purogene isn't just Sodium Chlorite in solution. There are other stabilizing ingredients in the Purogene formulation to tailor its reactivity. Purogene can be used activated with an acid (citric acid or lemon juice) to release the available Chlorine Dioxide for system disinfection. Or, it can be used un-activated as residual protection for bacteria. The bacteria themselves are acidic and when they encounter the formulation there is a release of Chlorine Dioxide to kill the bacteria. Because it's in a stable form, the remainder of the formulation stays in solution and remains un-activated until it encounters additional bacteria or something acidic. The by-product of reacted Purogene is ordinary table salt.
If you are able to remove all the liquid from Purogene it would not spontaneously combust. It would be pretty reactive, but it will not combust on its own. And, there's not going to be much of it. Generally speaking, it's actually a lot safer and much less toxic than bottled bleach.
Purogene has 2% (20,000 PPM per ounce) of available Chlorine Dioxide. It is not Chlorine Dioxide in a bottle. It is available Chlorine Dioxide.
You are correct in that Chlorine Dioxide is an excellent biocide and removes biofilm while killing more bacteria that chlorine. You are also correct that Chlorine Dioxide gas is always made on site and cannot be transported. But, again, Purogene is not Chlorine Dioxide, it is available Chlorine Dioxide. In the activated form (mixed with acid), Purogene in an uncapped bottle will last about a week. In a capped bottle, about a month.
As for the MSDS, you have a few things incorrect. It's actually 3.35% Sodium Chlorite. There is not a .1 PPM used rate as you state. The .1 PPM and .3 PPM limits are for exposure. The only time those limits are even an issue is during activation (after adding the acid). They have nothing to do with Purogene in water. When you activate Purogene there will be a release of Chlorine Dioxide gas and you should not hold you head over the container. But, the amount of gas release is small. You would almost have to concentrate it intentionally for it to be an issue. The new SDS doesn't even have those limits stated. The recommended residual available Chlorine Dioxide for drinking water treatment is 5 PPM (1 ounce in 30 gallons of water).
Hydrogen Peroxide is a pretty poor disinfectant unless you bring the level up high enough to be somewhat effective. What you get in the brown bottles is generally 3% HP. If you were able to fill your entire tank with 3% (30,000 PPM) HP you would kill some of the bacteria. For the tougher ones you have to about double that concentration to 7% or 70,000 PPM. For the really tough ones you would need closer to 27% (270,000 PPM) to be as effective as 50 PPM of activated Purogene for the same types of bacteria. You can buy 35% HP but you're gonna need a whole lot of it to actually do something. HP isn't used in water disinfection by itself, it's always paired with another process because it's a weak mirobiocide. It is not approved by regulatory agencies as a stand-alone disinfection treatment process.
Purogene is just about the most effective disinfectant available. It deals with the hardest to kill bacteria and does so with a very mild by-product: table salt. There really isn't much grey area as it has been tested side-by-side with other common disinfectants and shown to be incredibly effective when compared to other disinfectants, some of which have to be used at very high concentrations and some of which produce some very bad by-products. It's EPA registered and has been used in the airline industry for nearly 40 years to disinfect the tanks in airplanes of all sizes and the equipment used to transport water. Virtually every airframe manufacturer specifies only Purogene to maintain the water systems in the planes.
I hope I've been able to clear up a few things up.
Sodium Chlorite is a precursor to produce Chlorine Dioxide. It doesn't magically do this by itself. You must use chlorine or acid to activate it. Left to dry out it will spontaneous combust. Commercially it is supplied in as low as 3% solution for small applications and at much higher concentrations for large applications. If you do let it dry out and hit it with some acid you will be dead in a hurry if you breathe it. You can make a lot of money cutting the industrial version with water and reselling it. The lower percent watered down product is sold that way due to the fire hazard and environmental hazards as well of the concentrate.
Chlorine Dioxide gas in water is an excellent biocide and will remove biofilms while killing more bacteria than chlorine. However it is very lethal and dangerous and must be generated on site and is never transported. Google it and see how lethal actual chlorine dioxide is. It is also very easily gassed of and doesn't remain in the water very long.
I worked with chlorine dioxide generators on a large scale for many years and you don't buy it in a bottle or any other type container.
You are buying a little over 0.0335% sodium chlorite salt. (not sodium chloride) this is based on the MSDS dated 1994 on file by the parent company. Note the .1 ppm used rate as well on the MSDS. Supposedly 0.2% Citric Acid for the activator is added but don't show up in the SDS which is the replacement for the MSDS sheets of old.
I use hydrogen peroxide and just add it to the tank when I fill it based on the amount of water added. Bleach does have its drawbacks but there is no magical product out there that is safely and easily applied or the world would be using it.
This product can work on a limited scale but it is hardly anything new or magical. To sum it up a bottle of hydrogen peroxide will do the same thing and is a bit cheaper.
Do a little home work and see what you are investing in. I don't like to rain on any ones parade but this one is in a very grey area.
