Info-post: Stains: Iron, Copper, Silver & More

FAQ: "Stains & Metal Matters: Iron, Copper, Silver & More"


About copper and silver based 'sanitizers' . . .

Metal based treatment systems have been used in the pool industry for years, primarily to control algae. Regardless of the mechanism used, all work by adding soluble heavy metals (primarily copper or silver) to the water. These metals, when dissolved are "ions", thus the common term "ionizer", which is applied to a variety of systems that use some sort of electrical current to drive the metal off of actual chunks of copper, silver, or an alloy of the two. However, the copper "ions" added to the pool via copper sulfate (blue stone, blue vitriol, some 'root-killers', etc.) is exactly the same ion.

Let me repeat that: once copper or silver ions have entered your pool . . . they are all exactly alike*, regardless of whether they were added from a chunk of metal, a 'ionic filter bed', a liquid (like Pristine Blue (TM), or a granular solid, like copper sulfate beads.

Both copper and silver ions, in the right levels are effective at killing many types of algae, and some types of bacteria. But neither copper or silver are effective at killing viruses, which cause many types of sinus, respiratory and gut infections, and neither are effective at killing the amoebic cysts which cause some of the worst gut infections (giardiasis or cryptosporidiasis).

A further problem is that metal ions kill sl-o-w-ly, taking hours, or even days to kill pathogens and algae.

This is a serious problem, because in pools, most infections are transmitted quickly, from one person to another. These infections can be transmitted from person to person in minutes. Worse, infectious material (poop, snot, vomit, tears, or rarely, blood) left in pool by one swimmer can remain capable of infecting another swimmer for hours, if adequate levels of a fast acting sanitizer are not present in the water where the infectious materials are.

The ionizer people tend to argue that by using ionizers to control algae allows pool owners to operate with lower levels of chlorine. Based on lab results, that might appear to be true. Unfortunately, though the lab studies do examine how fast individual free-floating pathogens can be killed with low levels of chlorine + copper + silver, they ignore the fact that, in real pools, pathogens are not free-floating. Rather, they are almost always attached to something stringy (snot, vomit), gooey (snot, vomit, feces) or lumpy (feces) or particulate (vomit, fecal diarrhea). Attaching pathogens -- regardless of type -- to bits, bumps, slimes, and strings makes it very difficult to kill them, even with relatively high levels of chlorine.

The low levels of chlorine don't even stand a chance of doing so, in any reasonable time, precisely because chlorine is so effective at cleaning up 'goo'. What happens, with very low levels of chlorine, is that the chlorine in the vicinity of the 'bug' gets used up buring up the goo BEFORE it gets a chance to kill the 'bug'. By contrast, with relatively higher levels of chlorine, there's enough to both burn up the 'goo' AND kill the 'bug'.

The bottom line is simple: if people's bottoms (or noses or mouths) are in a pool . . . copper and silver are NOT enough to keep the water sanitary. ;)

There's another issue with metal based treatment systems: they stain things! :(

There are no exceptions to this: if you have enough metal in the water to be effective against algae, and to help with bacteria . . . you have enough to stain hair and pool walls. If you there's not enought to stain . . . then there's not enough to help kill slimeys and yucky things either.

This isn't a problem for everyone. Vinyl pool liners are pretty resistant to metal stains, and the patterns they are printed with tend to conceal the stains that do occur. Likewise, dark hair (brown & black) is also resistant to stains, and conceals the ones that happen. But, if you have a white concrete (plaster) pool, or family members with light hair (gray or blond), watch out! And, if you have children using your pool who have fine white blond hair from Nordic or Celtic genes, don't even think about allowing them into a metal treated pool That sort of hair can turn grass green. Really!

By the way, it's not chlorine, but copper that causes green hair. No copper, no green hair. Period. End of story. (It is true, that if there is copper in your pool, high chlorine levels will increase staining of all kinds, but without the copper, green hair just does not happen.)

So . . .

Do I recommend copper/silver based treatment systems? Not for pools. For fountains and such, where the goal is to keep things from *growing* in the water, I think such systems could be very helpful. But, in pools, copper/silver systems simply cannot keep the water safe. And if you use enough chlorine to do the job -- keep the water safe to swim in -- then you are going to have a real problem with stains. But, if you keep the chlorine low enough to minimize the risk of staining, then the water isn't going to be safe, if you allow multiple people to swim.

Also, the savings those systems produce is all depends on what kind of pool system you compare them to. Compared to a chlorine treated pool, operated by a pool owner following the Biolab 'Alex' system overdose, and then overdose some more . . . you could save a lot. But, compared to the poolowners here, who are following my recommended methods, and spending $25 - $30 per month for ALL chemicals, you won't save anything at all. In fact, even if you ignore the initial costs, and the electrode replacement costs, some ionizer systems come pretty close to that much in monthly electrical consumption!

Still, it's your choice.

The fact that copper/silver pools are not effectively sanitized only means you could get sick from swimming in them; it doesn't mean you will get sick. It's all a matter of the odds. If you are willing to take the risk, feel free to try them. But, I've never let my family swim in copper/silver pools.

PoolDoc
PoolSolutions.com / PoolForum.com

* Actually, there are two types of copper ions that occur in pools, depending on the electrical state of the ion . . . but the second one is useful only for causing black stains, and most often appears when pools with copper are heavily shocked (oxidized). This happens because oxidation (like with chlorine shock) is, at the molecular level, an electrical process!