Ozone, UV And Mineral Purifiers Can Lower Chlorine Use

by Barrett Kilmer July 3, 2012 8:36 AM
photo of shimmering water

Though chlorine has a long and glorious history of killing dangerous things in people's pools, some homeowners treat it like a pariah. In their estimation, it presents as many problems as it prevents.

The good news is that you can cater to these chlorine-averse customers by selling them on ozone, UV or mineral water treatment as ways to reduce the need for large doses of chlorine in their pools.

"All of these products, whether ozone or UV or minerals, are all promising the same thing: lower levels of chlorine," says David Goldman, director of product development, automation and sanitation for Zodiac Pool Systems, which makes a mineral sanitizer. "Now, chlorine is not a bad thing at all, but there are some people who are just comfortable with the idea of using less."

Here are three alternatives that can help them achieve that.

Ozone Generation

In simple terms, what an ozone generator does is split oxygen molecules (O2) in two, leaving single molecules that will then attach themselves to other O2 molecules to become ozone, O3, an extremely powerful oxidizer.

Del's units are installed on the return side and use a process called corona discharge (CD) to produce ozone.

"CD has an electrical power supply and it's attached to a glass-filled tube that has metal shavings inside it," says Jeff Jones, national sales director for Del Ozone. "The electricity goes though those metal shavings, and that's where we basically introduce oxygen in and suck ozone out."

Though Del Ozone is based in San Luis Obispo, Calif., Jones works out of an office in the Dallas-Ft. Worth area, one part of the country he says is increasingly accepting of sanitizing alternatives like ozone generators.

"We're really gaining some traction with all the issues with salt generators cropping up," he explains. "The issues with salt have been that salt is eating up hardscapes, plants and metals. The biggest problem we have here in Texas is the saltwater penetrating the stone, then evaporating and leaving behind salt crystals that expand and crumble the stone."

Even pool owners who like their salt generators can benefit from ozone, partly because the product "basically destroys anything that's in the water," Jones says, thus handling a lot of the work that would ordinarily be done by generated chlorine.

"I can marry my product with salt and actually help extend the life of the salt cell," he says. "We can blow the ozone right through the salt cell, and that allows you to turn the electricity way down, and salt cells on high power are susceptible to damage. It helps prevent scaling on them, too."

Jones estimates that considering two factors, the life of the cell in a salt chlorine generator can be extended from about three years to as many as six. For their part, the electrodes in ozone generators last around 15,000 hours, which depending on run time and length of the pool season, Jones estimates at between three and five years.

As for the combination of ozone generators and salt generators on pools, Jones says it's less common than the combination of a tablet feeder with ozone on newer pools.

"Then they'll throw in a mineral pack, and you're covering every aspect of water sanitation," he explains. "When you look at swimming pool water, you need three things: You need a residual, an oxidizer and a biocide. So you can use ozone to oxidize, a tablet feeder for a residual, then a biocide like Nature2 or Pool Rx."

With this combination, users can decrease chlorine residual from the normal 5 ppm down to 0.5 ppm because the ozone is taking on the task of oxidation, which normally uses up about 70 percent of the chlorine in the water, according to Jones.

Ultraviolet

Reducing chlorine use is one of the benefits of UV-sanitation, too. It also plays well with others, being capable of working with minerals, chlorine, bromine, biguanides, ozone and salt. But it's salt that's really the market driver.

"There are kind of two schools of thought residentially with UV right now," says Dave Callahan, who manages commercial sales for the Delta Ultraviolet Corporation. "We've got people who are trying to replace salt chlorine generators, and we have people who are trying to make them work better."

Like ozone, UV extends the life of a salt cell by enabling the user to turn it down, using less electricity and producing less chlorine.

"It's a considerable savings," he says. "Keep in mind, depending on what you're using for your system, the UV is going to be deactivating most of the bacteria and the living entities such as algae. Would you still use an algaecide? Probably, but you'd be using less. You'd also use less clarifiers, enzymes and other ancillary products. And less chemicals also means less balancing products."

Pressed on the matter, Callahan suggested savings of 50 percent on chemicals, cautioning that results may vary.

How It Works

Delta's UV sanitizers differ from ozone generators in a couple of key ways. For one thing, the UV treatment of the water takes place in the cell and nothing is introduced into the pool water. This happens in a relatively uncomplicated way, Callahan explains.

"What we are basically doing is re-creating the UV-C light wave that the sun produces. At 254 nanometers UV-C light will disinfect, to put it simply," he says.

Here, Callahan draws a distinction between what UV devices do compared with ozone or mineral sanitizers. They don't, in fact, kill anything. Instead, they render their prey inert by scrambling their cells in such a way that leaves them unable to reproduce. So, if a bather takes in a virus swimming in water treated with a UV sanitizer, that virus will be alive, yet completely harmless.

"If it can't replicate, it's not going to hurt you," Callahan explains. "So what it does is, non-chemically and without producing any byproduct, it renders any living thing that passes through it inert."

According to Callahan, the devices have a deactivation rate of 99.99 percent when used with proper flow rates. And the units are pretty simple: bulbs, crystal sleeves and electronics to monitor bulb life.

Like ozone, UV is considered a secondary disinfectant and as such can't be used without a residual sanitizer. He and his colleagues are careful to point this out.

"We had some natural pool guys come in and say, 'We want to use UV because we're not going to use any chemicals.' We couldn't tell them to do that, because then you're not providing anything to neutralize or kill within the actual body of water."

Cost-wise, Delta's UV devices go for about $1,200, installed, and the bulbs are about one-sixth the price of a salt cell, according to Callahan.

Another benefit is chloramine reduction, which is achieved by halving the flow rate on a variable- or two-speed pump, which increases the dosage to a range that destroys them, according to Callahan.

Minerals

Mineral sanitizers are effective killers, and like ozone and UV, reduce a pool's dependency on chlorine. In the case of Zodiac's Nature2 mineral sanitizing system, the residual can be kept at a low level of free and available chlorine.

But while Callahan and Jones eagerly touted their products as replacements for customers dissatisfied with salt-chlorine systems, Goldman stuck up for the units, which he says Zodiac sells in large quantities to happy customers.

"There are literally millions of pools with saltwater chlorine generators where they work great," he says. "There are a lot of misconceptions out there, though. You hear people say, 'My pool doesn't use chlorine.' That's one misconception. Others will talk about allergies to chlorine, which I've read is actually extremely rare."

He does admit chlorine generators were initially oversold to the public, but that if used properly the reported problems are largely avoided.

Zodiac makes units that combine salt chlorine generation and Nature2 minerals. We know the generator part of the unit turns salt into germ-killing chlorine in the pool, but what about the minerals?

Mineral sanitizer systems like Nature2 contain a combination of silver and copper, each with a specific purpose. The silver oxide is the sanitizer, so what it does is kill things in the water by interfering with the DNA of microorganisms.

The copper is an algaecide. A very effective one, according to Goldman, who says a less-is-more approach to using copper is preferred.

"Some people believe that putting copper in a pool will stain it, and it potentially can," he says. "With Nature2 we have a system that allows us to very accurately control the release of copper and the release of silver.

"So, in the case of the copper, the Nature2 product will release it into the water until it reaches an equilibrium of about 50 parts per billion, and as the copper is consumed after reacting with the algae, then more is released until it reaches equilibrium again."

A key difference with minerals is the silver leaves a residual, and while ozone is an effective oxidizer and UV is a capable sanitizer, neither can attack organisms that don't come into contact with it, Goldman says.

The minerals are delivered passively, and the units require no power. Initial outlay for a unit on an average sized pool is less than $200, and replacement cartridges cost around $80 and last for six months — a full season-plus in all but the warmest parts of the country.

"A residual sanitizer is still needed for dead spots in the pool," Goldman says. "And the level can be kept at 0.05 ppm."

That's not chlorine-free, but as is also the case with the reduced levels afforded by ozone and UV, it's as close as it's safe to get.

Comments or thoughts on this article? Please e-mail barrett@aquamagazine.com.



Barrett Kilmer, has been on the editorial staff of AQUA magazine since 2000. He has a B.A. in English from the University of Wisconsin - Madison, and currently lives in Madison, Wisc.

Comments (26) -

7/3/2012 12:57:36 PM #


I wonder how many indoor hot tub ozonaters would have had to be disconnected, if the EPA had decided to require the same indoor air quality that OSHA requires for a factory floor?

I still can't believe that my industry refuses to recognize how harmful and corrosive ozone is.  Take a drive up the Jersey turnpike on a hot sunny summer day and tune in the radio.  You'll hear the announcer warn that ground level ozone is too high, and that people with respiratory problems should limit activity and remain indoors.

We seek out diets rich in anti-oxidants because of the harm that oxidants can do to our bodies, and ozone is one of the most powerful oxidants known to man.

Not a week goes by that we don't get a call from a hapless customer with a new spa and an asthmatic child that simply can't use the tub because of the ozone.  They're ecstatic to learn about our ionizers.

Now I'm certain that my comments will elicit all sorts of defensive replies from the ozone industry, but you can't deny the science.

On the other hand, mineral sanitization is highly underrated by our industry.  We have thousands of customers with hot tubs that have been able to eliminate halogens completely.  Obviously, it's a bit more complicated with swimming pools, on account of the added pollution from rain, etc., so a low chlorine residual may still be required, but our hot tub ionizer customers use a tablespoon of MPS weekly to oxidize their water (after they're done using the tub for the night), and the rest of the week they do not have to share their dip with any harsh oxidizing reactions.

While you need to sanitize 24/7 (which the ions manage quite well), there's no need to oxidize the water 24/7!

Art Glick

7/3/2012 5:55:18 PM #


The selling of heavy metal ionizers,  ozone generators,  and UV  does not reduce the chlorine level needed in the vast majority of pools. To sell consumers these devices is not doing anyone any favors. That was fixed by the EPA. It needs to be  0.2 ppm free and available chlorine without CYA and that goes up when CYA is used to between 5% and 8% of the CYA level.

Chlorine oxidizes. Ozone oxidizes. Ozone also oxidizes chlorine. Added demand.  If anything is in the pool, chances are pretty good it will get oxidized by the available chlorine in the pool before it gets to the ozone. What does make it there is toast but how much is that in a residential pool? Aren't we trying to reduce the demand on the available chlorine?

UV hasn't hasn't proven to me quite everything is Hunky Dorey in that it can create certain disinfection by-products if the pool is indoors. Residential indoor air handling  systems aren't known for their volume. Some commercial pools have the same issue. Outdoor pools get the Sun's rays. No additional UV is required.

Heavy metal ionizers don't kill fast enough to meet the disinfection requirements, which aren't unreasonable, of the EPA. Person to person transmissions are possible.

Encouraging the sale of these types of devices for residential use is a lie, IMHO. Educating  homeowners rather than the short term gains (these things have high margins) is needed. Its not about money. People's lives matter. Cloudy water can kill. Its about people's health in a pool. I can see the slots on the drain cover screws in my pool, eight feet down.

There is a need to educate homeowners truthfully. They have guests and family in the water. Don't sell them products that can't reduce the chlorine needed. Chlorine levels in a pool can only be augmented or added to.

Scott Bair

7/3/2012 6:56:13 PM #

Mr. Glick wrote: I wonder how many indoor hot tub ozonaters would have had to be disconnected, if the EPA had decided to require the same indoor air quality that OSHA requires for a factory floor?

OSHA publishes a permissible exposure limit (PEL) of 0.1 PPM ozone gas measured as a time weighted average (TWA) over an eight hour work shift in any working environment. The US EPA publishes a permissible exposure limit of 0.08 PPM in the same eight hour time value (less than OSHA requirements). Spa ozone generator off-gas is regulated by UL and their official value for PEL follows EPA’s 0.08 PPM.  (Typically, the ANSI third-party validated spa off-gas level is far less than 0.08).  All spa manufacturers have a UL or ETL listing on their products, which means they must comply with UL off-gas regulations.

Ozone is listed by the US EPA as an antimicrobial oxidizer and is well known for its safe use in the spa and pool industry for decades. We do not advocate its use without a residual halogen and perhaps neither should mineral manufacturers.  In addition, whenever a bather gets into a spa, there had better be some oxidation. It is well known that the water quality is only maintained with proper filtration, proper disinfection and proper oxidation.

As a technical advisor and ozone system manufacturer, I never “deny the science”, nor would I use a forum such as this one to make uniformed or malicious comments about competitive products.

Beth Hamil
Vice President Corporate Compliance
DEL Ozone

Beth Hamil

7/4/2012 4:28:33 AM #

Water needs calcium or it will rob it from the plaster. The problem with salt versus a pool using calcium hypochlorite is that salt produces high ph so that the action of dropping the ph is a trampoline action...it wears away plaster. What customers wants a guaranteed plaster job every 5-8 years?

Michael

7/4/2012 1:05:05 PM #


Salt cells produce hydrogen. When the hydrogen gasses off, this can raise the pH, depending on the distance to the pool. The further away, the less is gassed off. Otherwise, the water's pH is unchanged.

Trichlor fed pools reduce the alk levels which van cause the pH to drop. It also added CYA,as does di-chlor. Too much CYA in the water make the needed FC level to go up too. CYA over 100 makes testing and shocking very difficult.

Cal Hypo add calcium. When this gets too elevated, scale deposits usually form. Using cal-hypo when this happens is just as bad as the etching a plaster finish can develop. Maintaining a CSI in a pool will keep plaster smooth.

Salt makes water conduct electricity. Old pools won't have the bonding needed. Stainless lights, rails, and ladders will rust and the sockets that hold the rails and ladders will corrode.

Some newer pools are designed using materials they shouldn't, such as softer, porous stone that breaks down. These will erode.

As you can see, whatever form of chlorine is used, it has its pluses and minuses.Maintaining a proper chemistry, overall, will keep a pool sparkly and minimize damages. Water is a pool's worst enemy, followed by the Sun. Educating pool care givers is the solution.

Scott Bair

7/5/2012 5:56:19 PM #

Quoting from the EPA's web site at...

http://www.epa.gov/ozonedesignations/

"Breathing air containing ozone can reduce lung function and increase respiratory symptoms, thereby aggravating asthma or other respiratory conditions. Ozone exposure also has been associated with increased susceptibility to respiratory infections, medication use by asthmatics, doctor visits, and emergency department visits and hospital admissions for individuals with respiratory disease. Ozone exposure may contribute to premature death, especially in people with heart and lung disease. High ozone levels can also harm sensitive vegetation and forested ecosystems."

Art Glick

7/10/2012 3:52:57 PM #


It would be pretty bad to breathe chlorine gas, stare at or expose skin to a UV lamp or eat copper or silver as well.  You can look up MSDS documents for all of the items. All of these items are safe and effective when properly used, as is ozone, which (I will repeat) is approved by the EPA as an antimicrobial oxidizer that can be safely and efficaciously used in swimming pools and spas by dissolving it in the water, and has been for decades.  No one advocates breathing ozone gas.

Clearly, you are singling out swimming pool and spa ozone generators and trying to make a case for their “unsafe use”.  I fail to see your science, but I can easily see your prejudice against any technology that is not sold by you or your company.

Let’s be clear on what the EPA actually says in its website entitled:

Ground-level Ozone Standards Designations
This web site provides information on the process EPA, the states, and the tribes follow to designate areas as "attainment" (meeting) or "nonattainment" (not meeting) the ground-level ozone standards established in 1997 and in 2008.

Breathing air containing ozone can reduce lung function and increase respiratory symptoms, thereby aggravating asthma or other respiratory conditions. Ozone exposure also has been associated with increased susceptibility to respiratory infections, medication use by asthmatics, doctor visits, and emergency department visits and hospital admissions for individuals with respiratory disease. Ozone exposure may contribute to premature death, especially in people with heart and lung disease. High ozone levels can also harm sensitive vegetation and forested ecosystems.

EPA will work with the states and tribes to share the responsibility of reducing ozone air pollution.  Current and upcoming federal standards and safeguards, including pollution reduction rules for power plants, vehicles and fuels, will assure steady progress to reduce smog-forming pollution and will protect public health in communities across the country.

Beth Hamil

7/12/2012 3:16:42 PM #

I'm not defending chlorine.  I think it's almost as bad as ozone.  As for copper, silver and zinc, the levels maintained in the water are many magnitudes of ten less than hazardous levels, and you can't say that about either chlorine or ozone.  I can only speak to all the hapless customers with asthmatic children that contact us because their child can't use their new spa with the ozonater connected.

And we DO sell ozonaters for ornamental ponds and such.  We just don't recommend it when human bathing is involved.

Art Glick

7/17/2012 4:36:57 PM #

We’ve uneventfully utilized UV + Mineral dispensing along with low-dose chlorine (including salt-conversion deices) on large water bodies, for nearly 20-years. Feed-store-grade copper-sulfate, fed from an of-line chlorinator was a common-device on indoor-mall-fountains, long before packaged sacrificial-anodes or dispensing devices were ever available. Even sanitizers or oxidizers must be utilized in moderation, just as we should control our intake of prescription-drugs, hot-dogs or beer.
Oxidization, as I understand-it utilizes oxygen to oxidize organics and soft-carbons. For example: Logs placed on a burning fire is consumed by the oxidization that occurs, per the oxygen-content, leaving behind the carbon (ash). Breathing the ash could be unhealthy, but fortunately OSHA and the EPA haven’t to-date, outlawed fire. Nature’s ozone likewise oxidizes “Contaminates” in the air, leaving the carbon-particles for us to breath-into the finite mechanisms’ of our lungs. It appears that somehow nature chooses to produce more-ozone when the hydrocarbon load in the air is excessive. Should our local-weatherman be offering an alert directed towards ozone or at the hydrocarbons expelled from his tail-pipe on the way to work, the hydrocarbons emitted into the atmosphere per the production of the fuel for his car or the power used to get ready for work? We rarely hear him offer an alert over the air contamination required to operate the TV or Radio-station. He like most that have ever visited a hospital or clean-room, may not fully understand the critical-role, our natural atmospheric chemistry plays. He may-also find it difficult to explain per laymen’s-terms, in a single sentence or two over-the-air.
Oxidization in water, be-it per halogens or ozone, likewise oxidizes the organics, while gassing-off the residual and leaves the carbon as TDS to be filtered-out. Still we experience far-less chloramine gas-off with ozone than with halogen residuals, indicating a more-complete oxidization. Isn’t it practical to uncover a spa for few-minutes before using, to allow the trapped organic-gases to escape? Another problem: Backwashing a sand-filter or cleaning the cartridge-filter “to-often”, can allow the TDS residual to elevate to undesirable levels. Seldom a problem experienced by my spa owners.
Of course, if you’re not oxidizing organics (pathogens) and eliminating them from-the-water, “Gassing-off” and “TDS filtration, may-not even be the issue of concern.
Please offer-up a simpler explanation, which Technicians along with my own weatherman can utilize.

Billy Irvin

7/19/2012 5:12:25 PM #


I have enjoyed reading this debate but, Mr. Irvin, "we should control our intake of hot dogs and beer" !!!?
  Now this argument REALLY has gone too far!!!

paul wahler

7/23/2012 10:19:32 AM #


Beth, thank you for clarifying. There are too many "quotes" online that are taken out of context and it's nice to see somebody take the time to clarify the facts. More and more customers are becoming educated in this industry and it's nice to see people taking the time to clarify misleading statements.

Art, as for the Ozonators having to be disconnected, most spas will only power the Ozone generator when the spa is running in the filtration cycle. Typically this is between 4-6 hours per day. Most people turn the high speed jets on when they are sitting in the spa, effectively cutting power to the Ozone generator which makes this a non-issue. I actually see the reverse effect of spa customers than you do. We sell thousands of replacement spa Ozonators to customers whose units have quit working. They notice the difference in the water almost immediately.

Billy, that was a great post!

Brian Richardson

National Service Manager,
Operations and Purchasing Manager
UltraPure Water Quality, Inc.

Brian Richardson

7/23/2012 3:14:46 PM #

We here at Almost Heaven have decided that ozone is so hazardous (perhaps even more so than chlorine!), that there is no place for it in any pool or hot tub ...we now feel that an ozonater is not suitable for human bathing applications.  

-So because you decided ozone is hazardous, we should stop using what has proven to be safe and effective for decades?? Hmm...well if you say so Art.

Gary L

7/24/2012 1:26:20 PM #

Gary and Brian - I take no issue with the "effective" portion of "safe and effective".  Same with chlorine, too.

It's the safety that concerns me, and the science that convinces me.  We've stopped recommending the use of ozonaters.  You can do whatever you want to do Gary.

Art Glick

7/24/2012 4:32:17 PM #

Ozone is just Oxygen.... but instead of it taking a long time to oxidize something , it is quicker, and does a good job of completely breaking things down.... it is the supreme oxidizer or purifier that is usable.....  However there is a necessity to the user to understand not its limitations but its powers.  It powers require its users to know just what is needed for a containment field...Its always been around ,but its users need to know it reactions and time frames for those reactions.... thought is not enough to be a user,.... thoughtfulness is necessary..It is the most useful purifier that we have.... but because of mans own limitations in learning how to use it , it rises and falls every decade.....  I use it in fishtanks, ponds, drinking water, swimming pools and in my air in my own home..... it was once built into clothes dryers..... I think hot tubs can use it , however , I dont myself , because I think bleach is easier to use .  

patrick venton

7/27/2012 7:21:35 AM #

Wow, two old "Hippies" battling it out on a blog.  Who would have expected that?  Absolutely loved the discourse. Thank you Beth and Art for one of the more interesting discussions I've seen.

Bruce

7/31/2012 4:45:51 PM #


Patrick - To say that ozone is just oxygen is a serious oversimplification of the science.  You need to understand the difference between atomic oxygen (O1) and diatomic oxygen (O2).  The act of "oxidizing" (i.e. burning up dead organic matter) is accomplished by O1.  Ozone is O3, which quickly breaks down to O1 and O2.

The O2 is the life giving form of oxygen and doesn't do much to clean a pool or hot tub.  Too much O2 can actually promote an algae bloom in a swimming pool.

Whether you use MPS, Ozone, Peroxide or something else to oxidize the water, the result is the same,  O1 atoms floating around looking to burn something.  They are "oxidants", and the damage that they can do to the human organism is the reason we seek diets rich in "anti-oxidants".

All pool and tub water needs to be oxidized from time to time.  My whole point is that I don't want to be in the tub or pool while that's happening, as it would be with an ozonater.  If you use a weekly treatment of MPS, you accomplish the same thing without having to share your dip with it..

Of course, you can imagine that ozone makers would disagree with my take on the subject.

Art Glick

7/31/2012 5:55:25 PM #

Doesn't your (Art's) last comment about ozone perhaps hinge on how the ozone is introduced into the water???  There are ozone systems that put the ozone in on the return side - basically on the return side - which I assume might put a fair amount of ozone into the pool.  But there are also systems that inject the ozone at the suction side - mixing the ozone with the water in the high pressure area of the pool pump.  Since ozone has an extremely short life most of the ozone is returned to O2 before the water carries it into the filter.  Very little ozone, if any, actually gets returned to the pool as I understand it.  Just curious what your take is on that...

Bill

7/31/2012 6:32:38 PM #

Ozone, in 86 degree water, has a half life of 12 minutes. This is normally more than enough time to make it from the suction side of a pool's pump to the pool. If the ozone does come in contact with something that can be oxidize, ozone will give up an oxygen atom, leaving a diatomic molecule of oxygen.

As ozone breaks down, the lonely oxygen atom seeks out another particle that can use it to make a covalent bond and the valence shell closer to being complete . If this happens to be another oxygen atom, great! The two together form a covalent bond and have a completed valence shell..

Valence shells need 2, 8, 18, or 36 electrons to be complete. Of all the elements in the periodic table, only the Nobel gasses have complete valence shells and cannot combine with any other elements or molecules. They are inert.

Pretty fly for just a High School guy. And that was a very long time ago. 10th Grade Chem. My chem teacher would be proud.  I'm now over a half century old. This is the net. I am not that ignorant to not realize that.

Scott Bair

8/2/2012 3:51:13 PM #


I would add that the reason ozone is introduce before filtration is to filter out any oxidized impurities. To add it after would simply send any oxidized impurities back to the pool. Why do it?

About the only things I can think of that ozone doesn't kill is algae and pathogens that are in the pool, waiting to hit the filter. That can be 5 turns of the pool's water. It's why ozone can only augment, not replace or reduce the need for chlorine.

BTW, ozone will raise a pool's Free chlorine demand and raise Combined. It is another reason it is added before the filter and chlorine is added after. This gives the ozone time to either oxidize or start to break down so it's effects on FC and CC are minimized.

Scott Bair

8/2/2012 5:00:29 PM #

Bill - here's the thing with introducing the ozone on the suction side - it will be even more damaging to your equipment!

Scott - thanks for the chemistry lesson.  It is pretty basic 10th grade stuff, isn't it?  You wrote...

If the ozone does come in contact with something that can be oxidize, ozone will give up an oxygen atom, leaving a diatomic molecule of oxygen.

And "something that can be oxidized" means rubber o-rings, gaskets and metal parts in the equipment!

By the way, it's my understanding that the O3 will give up one atom of oxygen quite easily, without much prompting.  The ozone doesn't need to come in contact with something to oxidize.  And then you have those nasty O1 molecules running around ready to oxidize any rubber, metal or DNA that they encounter!

Art Glick

8/2/2012 7:58:16 PM #

It's amazing what one can copy off the internet.  I am not sure what relevance the Noble gases (which you spelled incorrectly) have to do with my question to Art.  Anyway, it's really not worth debating as that was not the point of my post.  The point of my post was that it would seem that far more ozone would enter the pool water if it is returned on the return side of the pool.

Bill

8/7/2012 11:25:57 AM #

We must protect chlorine from uv with stabilizer. UV generators work at 254 nm. Chlorine is busted up by UV rays under 300 nm. Therefore, it seems like a UV generator is working against a regular poolman. With all the hoop-la about ozone, I will no longer install ozone generators on indoor pools. If you wish to do that kind of thing, it takes a contact tank and quite a production.

I have joined the 2000's. I now alternate shock using cal hypo and oxzone every other time.

Rob Lane

8/7/2012 11:30:23 AM #

In reference to Art Glick, you are right. That is why ozone injectors are the last piece of equipment in the mech. room. When the ozone is fed through the pump pot suction, it eats the equipment. That lesson was learned the hard way. For proper application, I like the Delzone people.

Rob Lane

8/7/2012 3:49:49 PM #

Rob,
Just wanted to let you know that your statement on UV is not correct; It’s true that UVC units disinfect at 254nm and that a properly sized unit will start to photo-chemically destroy mono chloramines at 40mJ/cm2 at 254nm but you would have to deliver at least a 200mJ/cm2 dose to start to see a measureable destruction of free chlorine.
Best regards,
Dave Callahan
DeltaUV

Dave Callahan

8/8/2012 3:22:16 AM #


I don't know why my spell check let that one go by. I suppose I had that coming since I just zinged my father for the same kind of thing. Karma. Smile

Ozone doesn't have the half life of a residual sanitizer like chlorine. I still don't see how sending it into a pool would help.

BTW, I am still friends with my science teachers from high school. Granted that sub shells are now taught about but the basic science is still pretty unchanged at that level.

Scott Bair

8/9/2012 1:01:14 PM #

Art,

I have spoken with pump and filter manufacturers and they have no issue with ozone introduced on the suction side of the pump on residential pools and, in fact, this method has been utilized successfully for several years.  And I don't see any warnings or cautions about this in a quick scan of the pump manufacturers Install Manuals??

Bill

Bill

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