Next ?? Silver Ions

[Chasville]

So silver ions are supposed to act as an anti-microbial agent right?
How? and why is it considered to be too slow?

I'm not talking algae here, so please don't comment on plant life.
Let's stay with bacteria and viruses.

 

[Guest]

In a nutshell, CT times for silver ions are very long. For a static system such as a water storage tank for potable water this is not a major problem since contact time can be ensured but for an open system like a pool the kill times are too slow to ensure sanitized water.

 

[Chasville]

What does CT mean?

 

[chem geek]

Chlorine concentration in ppm (C) times time in minutes (T) for a given kill amount (say, 99% kill). This post gives more info and links to other posts with even more detailed info. Generally speaking, what takes chlorine 1-2 minutes for a 99% kill (at typical CYA levels) takes silver 10-20 minutes and copper around 40 minutes, but this depends on the specific pathogen and concentration of these disinfectants. The metal ions are even less effective against viruses since the mechanism by which they work mostly requires the pathogen to be reproducing in order to effectively kill them (and viruses don't reproduce outside a host and even within a host they use the host's cells for reproduction). Metal ions are not oxidizers so are not "active" killers -- they are more like interference with certain cell chemical processes.

 

[JohnT]

So silver ions are supposed to act as an anti-microbial agent right?
How? and why is it considered to be too slow?

I'm not talking algae here, so please don't comment on plant life.
Let's stay with bacteria and viruses.

Curiously, blue-green algae that we have problems with in pools is actually a bacteria that photosynthesizes. Very interesting reading if you like knowledge just for the sake of knowledge. Google cyanobacteria.

 

[Chasville]

I just read a bunch of stuff on Wikipedia about algae, and cyanobacteria, while waiting for a process to run.
Lots of confusing terminology.
And eesh, yuck, slimey, blech, :tongue:

So the reason to keep algae or any growths low, is to keep the water as safe and non-toxic for humans.

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Products containing silver are not to be applied in marine/estuarine
environments or oil fields. Discharge of effluent into lakes, streams and
ponds or public water is subject to NPDES license restrictions. Water
treated with silver as a pesticide cannot be discharged into sewage systems
without notifying the sewage plant authority

From an EPA .pdf that I found in following CG's links. Boy did I wish I had found this two years ago.
Good thing I usually discharge my backwash into my landscaping.

Also from the same EPA R.E.D.

Silver, a naturally-occurring element, is registered for use in water filters to
inhibit the growth of bacteria within the filter unit of water filter systems
designed to remove objectionable taste, odors, and color from municipally
treated tap water; these bacteriostatic water filters account for over 90% of
its pesticidal use. Silver also is used to control several types of algae in
swimming pool water systems; this algicide use accounts for only about 3%
of silver's use as a pesticide.

Apparently the EPA recognizes silver as a "bacteriostatic" but not as a "bacteriocide". A huge difference.
Again, I wish I had found this stuff two years ago.

So, this explains why I have what looks like good clean water in my pool with the combination of the ionizer (silver and copper), the ozonator, and the frequent scrubbings of surfaces by the 'bot. The addition of the DE in the sand filter helps as well, by removing more of the small stuff in the water.

But the objections that everyone keeps making is that the water is not appropriately sanitized for use by people other than myself and my wife, and for frequent use. At issue is person to person transmission of disease, and animal to human transmissions since we have a large bird population and acquire frogs on occasion.

One of the problems with using ions in the pool, is that I have a test for copper, but not a test for silver, so I have to trust the ionizer's proportions.

The EPA article also makes me want to wear a dust mask when I clean the ionizer electrode, something I don't remember being cautioned about, and probably should were gloves? Or am I being too paranoid? I mean, I used to be an electronic technician, and I'm only partly crazy from the lead in the solder and other stuff.

oops, gotta go, probably starting to ramble anyway.

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But, what is the chemistry for how silver ions do their thing?

 

[chem geek]

But, what is the chemistry for how silver ions do their thing?

There is controversy about this and not a lot of good definitive science. Silver acts as a catalyst, which accelerates certain existing chemical reactions. Some of the ones that it accelerates are no doubt harmful to bacterial cells, most likely related to their reproduction or metabolism. Some other sources indicate that they more directly react with proteins and enzymes disabling their normal functioning, though I suspect that such reactions may involve binding (loose attachment) and not necessarily a chemical reaction (like oxidation, since silver is not an oxidizer). In any event, whatever silver does, it does so more slowly than chlorine, at least at concentrations low enough to prevent too much staining in pools or too much exposure to humans.

 

[Guest]

But the objections that everyone keeps making is that the water is not appropriately sanitized for use by people other than myself and my wife, and for frequent use. At issue is person to person transmission of disease, and animal to human transmissions since we have a large bird population and acquire frogs on occasion.
It is not even sanitized for one person to use, let alone two. Every person that enters a pool (including yourself and your wife) introduces urine, sweat, and fecal matter, no matter how clean you may thnk you are! You alreaedy mentioned the bird population.
One of the problems with using ions in the pool, is that I have a test for copper, but not a test for silver, so I have to trust the ionizer's proportions.
Outside of a laboratory water analysis there is no way to test for silver so the copper test and blind faith is used as a proxy,




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But, what is the chemistry for how silver ions do their thing?

There have been studies done
http://purestcolloid.com/pdf/3.pdf
but the exact mechanism is still a mystery.