40-50 years ago, swimming pools were plumbed with copper plumbing. The chemicals eventually decayed the plumbing, as did the velocity of the water. This put traces of copper into the water. The copper would eventually cause a blue staining of the plaster. It also reacted with the blond hair of some bathers, to cause that "green hair" effect - that is oftentimes blamed on the chlorine (remember: yellow + blue = green)!
The only positive benefit from the copper in the water, was a virtually algae free pool. Why, do you ask?? The copper (and actually all heavy metals) is an algaecide. It interrupts the plants ability to photosynthesize, thereby killing it.
As pools were eventually plumbed with plastic pipe, pool chemical companies started to manufacture liquid algaecides that contained heavy metals (primarily copper, nickle, and silver). Also in the solution, was a sequestering agent, sometimes also called a chelating agent. The purpose of this additive, was to keep the metals in solution in the presence of variations of high & low pH. Without these additives, in the presence of pH extremes, these metals would precipitate out of solution, staining the pool plaster. These metals do not evaporate out of the pool, and therefore become concentrated in the pool water. Another disadvantage of liquid algaecides, is that these additives eventually wear out.
Because of concerns over the environment, plaster staining, and green hair, these heavy metal algaecides lost favor - though they are still available.
When the industry shifted away from adding metallic algaecides to the water, along comes a different delivery system.... Ionizers (active & passive) which are nothing more than a twist - high-tech dispensers of the outdated & environmentally unsound metallic algaecides.
So along comes some P.T. Barnum types with a "NEW & IMPROVED" whizz-bang device that offers a "CHEMICAL FREE POOL!" In reality it was nothing more than a different method of delivering the same heavy metals into the pool - an erosion feeder. Instead of pouring the liquid algaecide into the pool, they micro-dose it over a longer period of time - with the same results! These are merely a small tank or module plumbed in the piping at the equipment pad. There is a replaceable cartridge within the tank, that emits heavy metals into the water when the pump is on.
They even came up with a fancy new names for these units, "mineralizers," "natural minerals," and "ionizers." And yes, they do put "natural ions" of heavy metals into the water. But cow manure & algae are "natural" too, and people don't want them in their swimming pool either! These cartridge units are collectively known as "passive ionizers." Some tried to hide the fact that they contained heavy metals, and marketed themselves as "natural mineral cartridges." What ever they call themselves, they all put metals into the water. These type of devices are marketed under such trademarked names as: Frog, Nature2, Smart Pure, DuoClear, Pool Rx, Elite Minerals... (the trademarked names belong to their respective owners).
These were marketed to pool owners as a "safe & chemical free way to keep the pool crystal clear with minimal chemicals" (notice that it said minimal - not NO chemicals!). To the pool industry, it was marketed as a re-occurring profit center. Why? Because the pool owner would have to come back to you for replacement cartridges every 3 months!
So, along comes the Ringling Brothers who join the P.T. Barnum Circus & say, "I can offer you all the benefits of the mineral cartridges, without the constant need to replace the expensive modules." and what pray tell, kind of snake oil do they have in their jar??? It is an "active ionizer," wherein electricity is used to cause the erosion of heavy metal plates within a cylinder plumbed into the piping - emitting heavy metal particles into the water.
Again, they are advertising their products as being "chemical free." This may work on the algae present in the pool, but they do nothing to provide a residual sanitizer that will kill the biological hazards or oxidize the bather waste in the pool. Some systems utilize what they call "active oxygen" or what smart people call ozone to kill the bio-hazards & oxidize the waste. However, once the pumps shut off there is NO RESIDUAL SANITIZER/OXIDIZER present in the water! These are marketed under the trademarked names of: EcoSmarte, Eco-Smart, Thompson Tec, Ionizer, Floatron, P-50... (the trademarked names belong to their respective owners).
I do not know how any of these modern systems can purport to provide any residual sanitizer to oxidize bather waste (urea), decompose hydrocarbons (suntan lotions, oils, shampoos, soaps, make-up, cream rinse, etc.), or how they kill viruses or pathogens (that are not plants).
Since the pool water will contain "heavy metals," the pool water absolutely cannot be discharged into ANY street, gutter, storm drain, or waterway (creek, stream, lake, etc.), as it will kill the ecosystem there. Many municipalities will not even let this water containing heavy metals be introduced into their SANITARY SEWER systems. It is just too difficult for them to remove these heavy metals at the sewer treatment facility, before discharging the waste water into the environment. And unlike chlorine, these heavy metals cannot be neutralized.
With all of the old issues of metallic staining & current issues of electrolysis occurring in swimming pools, personally I steer clear of these units or ANYTHING that introduced more metals or electricity into the water. Why in the world would I want to add more metals to the water? They do not evaporate & only build up, creating a concentrated soup of goup.
Over the years, environmentalist and the spread of mis-information about chlorine, have given chlorine a bad rap...
The facts are plain & simple: it is not the chlorine that causes bather discomfort. It is almost always from other water chemistry issues, and almost always due to the lack of proper chemical maintenance, testing, and incorrect dosing of chemicals.
Among the most common complaints: itchy skin (too little chlorine), burning eyes (bad pH or too little chlorine - ammonia compounds), green hair (excess copper), are all attributed to other factors... but ignorant people immediately point their finger at the chlorine - because they "smell" what to them must be chlorine (but are actually chloramines).
These same people sense the strong "chlorine" smell around a commercial or an indoor pool- and immediately assume that there is too much chlorine in the pool.... when what they are smelling is actually resulting from the LACK OF CHLORINE! What they are smelling are the chloramines (ammonia compounds that are formed when chlorine combines with bather waste) off gassing.
This is why you "smell chlorine" on your skin after swimming - but in reality, you are actually smelling your perspiration that has combined with the pool's chlorine that formed chloramines (ammonia compounds) on your skin!
The only real "new"technology is ozone (though it has been around for 30+ years). Done properly with sufficient contact time before re-entering the pool or spa - it has awesome effects on the water quality. Ozone works synergistically with the chlorine, taking over the business of oxidizing bather waste. Since ozone is a thousands times better oxidizer than halogens (such as chlorine, bromine, hydrogen peroxide), it takes over those responsibilities, allowing the halogens to work as sanitizers. The ozone will also kill biological pathogens & viruses, which ionizers will not.
I have personally been toying with ozone for over 18 years. I have 2 separate systems on my personal pool, plumbed into the filtration & vanishing edge systems. I have tweaked my own contact chambers & ozone destruct units to provide additional contact time & to be more effective.
THERE IS ABSOLUTELY NOTHING WRONG WITH USING LIQUID CHLORINE. To be politically correct & environmentally sensitive, we call it "bleach." Chlorine has been used as a pool sanitizer for over 100+ years. It is used to treat drinking water in almost every city in the world. It is used in almost every commercial swimming pool in the world to maintain clear, safe, and sanitary water.
People who do not understand how chlorine reacts with contaminants, heavy metals, and other chemicals, continue to spread myths about what chlorine does & does not do. For example, it does not turn hair green, but copper does! You cannot smell it around a pool, even at 3-5X the normal dosages, but you can smell chloramines (which are a result of too little chlorine). At the correct levels (1-3 ppm) it does not burn the eyes, but incorrect pH or chloramines will! When water containing chlorine must be dumped into a storm drain or sanitary sewer, the chlorine can be neutralized!
People who claim that they are "allergic" to chlorine, in almost every case are really experiencing reactions to the chloramines - which can cause itching & rashes. Someone experiencing "allergic reactions to chlorine" (actually the ammonia compounds/chloramines), could additionally be experiencing an allergic reaction(s) to any of the countless biological contaminants that accumulate in a pool (or worse yet, a spa) when the chlorine levels drop too low:
- Molluscipox virus.
- Mycobacterium spp.
- Staphylococius aureus.
- Leptospira interrogans.
- Trichophyton spp.
- E. Coli
- Human pathogens: blood, saliva, feces, urine, perspiration, mucus
- Acanthamoeba spp.
- Human papilloma virus.
- Legionella pneumophila
Additionally, alternative treatment manufacturer's and environmentalists point to the fact that chlorine is a carcinogen. Yes it is, but if the studies are investigated, one will note that the prolonged exposure, dosage quantities, and chemical concentrations of chlorine are way beyond what any normal human being will ever ingest over many lifetimes. Again, it is the "chicken little syndrome" - "the sky is falling, the sky is falling..." Did you know that ingesting too much water, too quickly, can kill you??? Does that mean that we should outlaw the drinking of water??? Of course not, but in moderation, the exposure is more than acceptable.
Depending on the scope of the project & chlorine needs, we use barrels to store liquid bleach that is delivered. Where large quantities are needed, say for example on Olympic sized swimming pools, we'll install an on-site electrolytic production. The electrolytic production also creates sodium hydroxide, which is collected for use in buffering the pH.
On site production doesn't always generate enough sodium hydroxide, so pH buffering is augmented with either C02 gas (it forms carbonic acid when injected to the pool water) or a 4:1 muriatic acid solution (4 parts water:1 part acid). At this ratio, the "boiling point" (vapor point) of the acid is reduced, so that you do not get fumes. As an added precaution, the chlorine & acid barrel bung openings are kept sealed & barrels are vented to the outdoors with a 1/4" vent tube.
For water chemistry management and to provide an automatic & instantaneous responses to the demands for additional (or fewer) chemicals (due to 30 kids in the pool, a 100ºF+ heat spell, or a cool weather front), my preference is an automatic ORP/pH controller (CAT Controllers & Acutrol are my 2 brands of preference). It monitors the water, responding to the additional demands placed upon the pool by the environment or bathers, by controlling 2 fixed rate peristaltic pumps (Stenner is my brand of preference)- delivering chlorine & the 4:1 acid solution. Coupled with an over sized 24/7 ozone system, you have as close to a trouble free chemical system as is humanly possible.
Chlorine has been the subject of a lot of false information, much of it spread by these P.T. Barnum's, so they can sell their snake oils. But once their products are actually dissected, they are found to be nothing more than high-tech delivery system of an old, dis-proven, and environmentally hazardous methods of delivering heavy metals into the water & environment.
Ecosmarte, Ecosmart, Nature 2, Frog, Pool Rx, Stenner, CAT, Acutrol, are all trademarked names & are owned by their respective owners. Theirs names are used here merely for reference.
Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa