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Toxin-Free Choices

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1 3 18JC0Wrapping up his series on a comprehensive approach to healthier pool water, John Cohen goes into great detail in defining system components and making specific product recommendations.

Those of you who’ve followed along with this series know how personally I’ve taken my quest to provide interested homeowners with toxin-free pool and spa water.

It’s a goal I’ve pursued since I started in the business in the 1970s, but a fire was truly lit under me by my daughter’s illness and my growing sense, as related in the first article in this series (click here), that what I was learning about her illness and the ways the human body works were all somehow related to what I was after in my pools.

I’ve spent a lot of time alone in this pursuit, because toxin-free pools had no history to speak of when I started paying attention and following research of the kind I discussed in the second installment of this series (click here). Yes, there were some ozonators and ionizers and a few other relevant systems on the market, but I had no sense that anyone else was out there on the frontier looking for ways to synthesize an approach that would lead to something meaningful.

Happily, I’m not alone on the leading edge anymore: Manufacturers in particular are interested, and that gives me great hope. After all, if non-toxic approaches happen to align with their commercial interests, we might really get going on what I see as an inevitable path away from traditional approaches to sanitizing pool and spa water into a new age in which non-toxicity becomes the daily, conventional approach.


As I’ve worked toward that goal and have done my research, I’ve always drawn support and encouragement from history.

As far back as 1200 B.C., for instance, the Phoenicians stored water in silver bottles to prevent microbial spoilage. The Greeks and Romans hopped on that potential, too, dropping silver and copper coins into water vessels to keep their contents drinkable. (Their impulses weren’t infallible, however, as the Romans managed to poison themselves with lead-based plumbing!)

1 3 18JC1The great Hippocrates noted the healing benefits and disease-preventing properties of silver, and his path has been followed by countless medical practitioners ever since. Nineteenth-century American pioneers crossing the Great Basin treated dysentery with silver and put copper and silver coins in water and milk containers to slow bacterial growth.

The 1800s also saw the use of silver-thread sutures in binding surgical wounds and of silver nitrate solutions for prevention of newborn blindness and as a treatment for typhus and anthrax.

By 1785, ozone gas had been observed as an emanation from electrical machinery. By 1886, the ability of this material to disinfect polluted water was recognized. In 1887 the first public pool in the United States opened in Brookline, Mass., and had an ozone-based water-treatment system.

By 1891, German scientists had definitively proved ozone’s effectiveness in destroying bacteria. In 1893, the first municipal water system treated by ozone was initiated in the Netherlands.

1 3 18JC2The Amish seem always to have known about hydrogen peroxide’s utility in water treatment and in numerous agricultural applications. They sprayed it on their string beans after the first harvest and were pleased by additional pickings on the same plants later on. They sprayed it on their cabbage, cauliflower and potatoes and noticed that bugs left them alone. They saw it as safer than any available pesticide in the diluted form they applied and observed that it harmed neither animals nor children.

The application of these technologies to swimming pools and spas came along much later – indeed, not until the 1980s, when some spas started being equipped with ozonators. (Today, of course, every major spa manufacturer includes an ozone option as part of their equipment packages.) On a much more personal level, I was called a snake-oil salesman when I rode around treating my pools out of 500-pound containers of hydrogen peroxide, but now it’s sold in just about every pool store in the country.

And now the time has come: To have real, progressive change in the swimming pool industry, we must begin working with mechanical systems that produce more than the sum of their individual parts and replicate the perfect systems that the human body and nature have developed.


Below is a long list of active, available systems I’ve examined, seriously considered or used through the years. The list is comprehensive, and I now draw from it item by item based on the specific needs of the project at hand with respect to factors including vessel size, anticipated use, sun and wind exposure, my clients’ desires and, of course, their budgets.

q Ozone

This disinfectant/oxidizer eliminates chloramines and kills all known bacteria, viruses, cysts, yeasts, molds and mildew while also reducing most chlorinated hydrocarbons. In my systems, corona-discharge ozonators are usually but not exclusively the way to go: Their high-voltage generation produces antimicrobial oxidation that sanitizes and disinfects and is highly effective against biofilm; reduces halogen levels; eliminates disinfection byproducts; and prevents infectious outbreaks.

1 3 18JC3Ozone is 10,000 times more effective than chlorine in killing a range of common pool pathogens and 25 times faster than hypochlorous acid in killing the dangerously common E. coli bacterium.

Finally, ozone is also a microflocculent that clumps inorganic and organic contaminants together during the oxidation process.


There are three possibilities I’ve explored here, including cartridges charged with combinations of colloidal silver, coated limestone and silver chloride; cartridges that use calcium and magnesium ions to act as polarized magnets that transmit energy to ions already forming tartar, thereby dissolving it; and units using zinc oxide, which kills 15 strains of candida, staphylococci and streptococci bacteria, pyocyaneus and most infectious bacteria.


A toxin-free approach can be served by up to three forms of ionization, including systems in which low-voltage D.C. currents activate copper, silver and zinc ions, thereby releasing into the water chemical agents that effectively kill algae, bacteria, fungi and viruses. There’s also a system in which mineral colloids, including zinc, sacrifice themselves to inhibit galvanic corrosion and stains while also providing some water-sanitizing effects.

1 3 18JC4In addition, there’s a silica-sand filter saturated with colloidal minerals that are activated as water passes through the very fine metal particles. I’ve also worked with another unit in which an ionizing capsule produces positively charged copper and silver ions that form an electrostatic bond and disrupt microorganisms’ cell walls. Palladium, zinc and carbon are part of the essential mineral combination here: Their positive ions attack the sulfur-containing amino-acid residues produced through photosynthesis.

qAdvanced Oxidation

In these potent sanitizing and disinfecting systems, aqueous ozone is exposed to ultraviolet light and decomposes into hydrogen peroxide – which continues to react with the ultraviolet light in turn to create hydroxyl free radicals. These hydroxyls are potent, fast-acting disinfectants that, when combined with split oxygen molecules, create oxygen radicals that can safely be injected into pool plumbing along with a residual level of hydrogen peroxide.

qAdvanced Filtration

This is one of the areas where conventional thought needs complete revision. What I’m pursuing is about more than just one form of filtration and moves beyond passively entrapping micron-scale debris, algae, bacteria and other contaminants for backwashing to make filtration an active component in creating toxin-free pools and spas.

The options start with a high-oxidation media that, through catalytic reaction, remove iron, manganese and hydrogen sulfide from the water. There’s also the shower-water-recycling system invented for the U.S. space program: It uses an inline microfilter charged with nanocapsules that remove 99.9 percent of the viruses, bacteria, toxins, metals and oils that flow through the system.

1 3 18JC5Another approach is a modular wastewater treatment system that removes arsenic, heavy metals, toxic organics, ammonium and a broad range of contaminants through screening and filtration; ozone disinfection and ion exchange; and liquid/solid separation through microfiltration. Advanced oxidation through a gas/liquid mass-transfer reactor is another possibility here, along with ozone-generation and ion-exchange units using zeolites, a material that polishes water while destroying ammonia-related molecules.

Active carbon fusion is another possibility as well. Here, a process is used to fuse activated charcoal to metallic silver atoms, creating a material that clears away suspended particulates, dissolved material and bacteria while interfering with algae growth, fighting corrosion and improving water clarity.

High performance filtration using regular activated carbon removes hard-water contaminants and extracts dissolved substances, human secretions, heavy metals, trace nitrates, sulfates, nitrogen, pesticides, hydrocarbons, colorants, detergents and chlorinated organic residues via a micron-scale pre-filter (for rust, various sediments and silt); a soft-grid filter (for scale prevention); copper, zinc and minerals (to reduce levels of chlorine, water-soluble heavy metals, bacteria and algae); and activated carbon (for herbicides, pesticides and other chemical compounds). The filter unit has a bypass system to capture any remaining sediment and organic particles (down to fractions of a micron) and an ultraviolet light chamber for additional bacteria and virus protection.

1 3 18JC6There are catalytic reactors used to soften hard water and remove dissolved substances, human secretions, heavy metals, trace nitrates, sulfates, nitrogen-type pesticides, hydrocarbon, colorants, detergents and chlorinated organic residues. And finally, there are regenerative media systems that use perlite-coated media capable of filtering out particles at the one-micron level. The virtues of this system have to do with convenience: high flow rates with long intervals between backwashes.


The toxin-free pool is not chemical-free: We still need ways to remove mono- or copolymer flocculants, metals, phosphorus, biosludge, soaps and other particulates that, left unchecked, result in scum lines, foam and stains.

One of these liquid products is hydrogen peroxide, an oxidizer that is more active than chlorine and will also neutralize chlorine. Its extra oxygen atom enables it to burn living organics, inorganic oils, sludges and biofilms and kill bacteria and viruses.

We also need to add coagulants that make tiny particles mass together for easier removal by filtration; flocculants to bind solids together, clarify the water, break down scale and ensure more complete filtering; sequestering agents to keep metals in suspension; chelating agents that bind up metal ions and keep them from reacting with other materials in the water; and clarifiers (generally polyacyrlimides, but in a non-toxic version!) that consist of crustacean shells that gather up contaminants in long-chain polymeric molecules, using their positively charged hooks to form neutral, buoyant flocs and effectively removing suspended solids from liquids.


These materials react with non-living organic waste, speed up chemical reactions and accelerate the breakdown of those wastes. Those I’ve used have included very aggressive industrial enzymes that eat each other after a very short active life and are used to target wastes in a specific category – for our purposes, fats and oils.

1 3 18JC7The most common enzyme in use is a broad-spectrum variety that is stable and has a shelf life measured in years. These products contain a range of co-enzymes that catalyze thousands of helpful chemical reactions. Finally, for pools treated using conventional chemistry, there’s a non-toxic, microbe-decomposing enzyme to protect cyanuric acid levels.


A corrosion and scale inhibitor, borates buffer pH and decrease the solubility of carbon dioxide, thereby starving algae spores.


There are three wave forms useful in reducing levels of scale, total dissolved solids, biosludge and phosphates. These are magnetism, which chelates total dissolved solids and thereby slows scaling while stimulating ionization processes; sonic systems that use ultra-high-frequency radio transmissions to break down calcium bicarbonate and magnesium bicarbonate crystals into carbonate – a material that does not bind to surfaces; and ultraviolet waves that inactivate the DNA of bacteria cocysts and pathogenic microorganisms without leaving residual disinfection byproducts. Germicidal ultraviolet light also alters and disrupts algae, bacteria, viruses, mold spores and protozoa, breaks down chloramines and is partially effective against cryptosporidium.


Plants have long been used to disinfect water and keep fish happy and healthy in ponds. In recent years, larger bog-filtration systems have also been used in creating the class of watershapes known as natural swimming pools. These systems work through epuration, using plants that encourage the growth of beneficial bacteria, bind phosphates and have root systems that effectively absorb, filter and clarify water. In addition, there are large, phosphorus-binding filter-grid systems that also have carbonators.


Through all my years of research and experimentation related to toxin-free pools, my company, Green Pastures Group (Topanga, Calif.), has been offering its clients systems that rely on three synergistic heavy hitters drawn from categories listed above – namely, advanced oxidation, ionization and advanced filtration.

Our pools and spas use the advanced oxidation system manufactured by Clear Comfort (Boulder, Colo.); the cathodic silver/copper/zinc ionization system from Almost Heaven Group (Renick, W.Va.); the submersible water-activated silver/copper/zinc/palladium/carbon ionizer from AquaSmarter (Niagara Falls, Ontario, Canada); and the fused carbon/silver advanced filtration system from Cartis (Brignais, France).

We complement and support these systems with the IntelliChem smart pH controller from Pentair (Sanford, N.C.), the zinc-anode electrolysis inhibitor from Pool Tool (Ventura, Calif.) and liquid hydrogen peroxide (27 to 35 percent concentration) from Leisure Time (Atlanta, Ga.).

1 3 18JC8For waterfeatures that involve human contact with water but without immersion, the program is altered just a bit: We use either the advanced oxidation system from Clear Comfort or the HydroRite system from Hayward (Elizabeth, N.J.); a corona-discharge ozonator from either Clearwater Tech (San Luis Obispo) or DEL Ozone (based in San Luis Obispo and now owned by CMP of Newnan, Ga.); hydrogen peroxide from Leisure Time; and enzymes from Natural Chemistry (Norwalk, Conn.).

In construction, I (and many other builders) use the newly developed colloidal-silicate, flexible, cementitious, multi-layered, LEED-Certified waterproofing systems – from Basecrete USA (Sarasota, Fla.), Dry-Treat (Andover, Mass.) and Valcon Industries (Sarasota) – and concrete substrate impregnators and densifiers.

These material technologies greatly assist the maintenance and life of plaster, stone, tile, grout, and all concrete watershape elements and contribute to overall water quality by lowering levels of total dissolved solids and water hardness while mitigating many of the leaching, delamination and water-loss issues associated with cementitious surfaces. All in all, using these materials assists in sustaining toxin-free watershapes.

One key limitation to development of toxin-free approaches is the general unfamiliarity and lack of curiosity within the service community about these systems and a tendency I’ve observed of a willingness to trash installed systems and “help their clients out” by converting toxin-free pools back to chlorine-treated vessels. This is an issue that must be dealt with through education and exposure, but it’s unlikely the situation will change until more designers and builders follow this path and pull service professionals along in greater numbers.

My colleague Steve Staples (Chlor-Free Co., Simi Valley, Calif.) maintains and services my non-toxic pool systems and reports meeting with doubt and skepticism among his peers when he suggests the importance of weaning ourselves from chlorine addiction and moving along to the new approach to water treatment he now accepts and endorses for the good health of his clients.


As you evaluate and absorb the contents of these three articles, think about the perfect systems at play in nature and consider the fact that even our great galaxies thrive through a grand-scale form of plumbing: If not even light can escape the gravity of a black hole, it’s a small step to conjecture that even the great cosmos has galactic vortex drains that scoop up masses of cosmic debris (and entire suns!) in pursuit of purification processes required in all areas of the physical universe.

I know that I am still essentially a lone wolf in these perceptions. But every day, with every installation, I’m becoming a more hopeful lone wolf. Care to join me on the new frontier?

To read Part 1 of this series, click here.
To read Part 2 of this series, click here.

John Cohen is owner and founder of Green Pastures Group, a watershaping and landscape-design firm based in Topanga, Calif. Cohen’s career began in working with his father, planting trees and installing landscapes for upscale properties and public spaces in southern California. He founded his own firm in 1975 and has since won a range of awards and appeared on episodes of design-oriented television shows, including “Backyard Nation” on The Learning Channel. Mostly self-taught, Cohen also studied Chinese gardening at UCLA. A pioneer in the field of non-toxic water-treatment systems, his projects include highly stylized and distinctive watershapes and landscape compositions for upscale clients throughout southern and central California, including the Beverley Hills Hotel. His work has also appeared on the cover of Architectural Digest.

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