Nature 2?

[sasha]

Odd that you say silver is a "great" sanitizer with UV light but discount its effectiveness with low levels of free chlorine. I think your only negative point is that such a low level of free chlorine would be rapidly depleted.

Silver, because of its lower reactivity, would not be depleted as free chlorine would. Silver would be persistently available unlike the free chlorine that is so reactive it gets used up. That might be just enough to get you through until more free chlorine comes on line providing those fast kill rates needed. In this sense, silver would be supplementing the disinfection properties of chlorine.

There's no measurement I'm aware of that would describe silver complexed in solution either as a AgCl precipitate, complex, or colloid that would totally discount its possible effectiveness. And of those other elements you list besides chloride, there's little reason to think those would be principle players in silver equilibria. I'd be more concerned about low levels of sulfide in the water reducing silver concentrations than a possible redox reaction between silver and some other trace metal ion. The solubility product constant of silver sulfide is several orders of magnitude lower than silver chloride.

Plus, who's to say the possible action of silver isn't simply suppression of formation of biofilms on surfaces that silver species have deposited on? Perhaps the formation and presence of these biofilms has more to do with the dynamics of bacterial counts in the water than has been traditionally assumed. There's a number of surface active silver products on the market.

I believe we tend to think in a simplistic model of disinfection where there needs to be a specific residual concentration of an agent to attain a specific kill rate for specific organisms. This is appropriate, but in the Nature 2 system, you should always have at least 0.5 ppm free chlorine anyways. This, for the most part, provides a sufficient kill rate and arguing about the slow kill rates of silver alone is a moot point. And when you point out that these other elemental species "decrease silver in the system", you're referring to a residual concentration that may be only part of silver's disinfection action.

I think silver is always in the system, in one form or another, whether in solution or on surfaces, and I would be hesitent to assume I understood the efficacy of all those forms without any data. I think there's some benefit, regardless of the mechanism, but at what cost?

The principle issue becomes one of cost and value to the customer, and as such, Nature 2 is a very poor choice for consumers. Of the active agents Nature 2 apparently provides (silver and copper sulfate), the amounts are worth a very small fraction of the product cost of almost $100. That's enough to convince me to never buy the product.

But whether it's Nature 2 or other products such as simplyblue etc., your gripe shouldn't be with the companies or salesmen trying to make a living. It should be with your Federal and state agencies who have a responsibility in protecting consumers from ineffective products related to public health. Writing a few letters to positioned people in those agencies would be a more valuable and effective exercise than banning people from forums such as this who promote those products.