Not sure where you read that salt will eat through plaster, it won't. The salt can affect metal objects like handrails, heater coils, etc. But there's not a lot of solid data on that either (it could be due to a chemical imbalance, or cheap improperly finished metal being used for example). There are many, many people on here running SWGs that are very happy with them (me included). Regarding ozonators and ionizers, there's been a lot of discussion about those as well and reports vary. Some people have algae problems that they can't get rid of while others have had good luck. I think the consensus is you have to run those with conventional chlorinators, they can lower the chlorine needs but they do not clean the water 100% on their own.

lindamarie,
I have been looking into this question myself as our family has chemical sensitivity issues and came across this research study yesterday that I will link below for you. It's a bit technical, but the gist is that ozonation produces potentially toxic by-products of its own and most are scientifically uncharted territory ("emerging disinfection by-products") at this point so we don't know much about them.

I found the following statement within the abstract to be a fairly effective summation of the whole (DBP's=disinfection by-products): "However, the levels of many emerging DBPs are increased by alternative disinfectants (primarily ozone or chloramines) compared to chlorination, and many emerging DBPs are more genotoxic than some of the regulated DBPs."

I had been considering a combination SWG & ozone system, but don't think I will after all.

Here is a link that might be useful: Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water

The World Health Organization recently published their healthy pool guidelines. They site Ultraviolet systems as the only sanitizer that will kill all the bacteria, germs, virus etc, that does not generate any DBP's.

UV does need some form of residual to control algae growth on the sides of the pool. Hydrogen Peroxide, .05 ppm of chlorine, or simply wipe the sides often to get the algae in susspension so it can pass through the system.

A comparrison of UV versus, salt, ionizers or chlorine can be found at : http://rx.halcyontec.com/rxvsothercomparisonchart-i-5.html

We have an ozonator and I love it. I was very skeptical at first because I had a predisposition that they were ok for a spa but just didn't have the "power" necessary to do a pool because of the load. Now, I basically have had to drop that thinking by the way side. Also, I have had a BBB pool and a SWCG pool before. I'm beginning to believe that our Ozone pool is the next best pool setup to perhaps an Ozone/SWCG combination possibly being the very best. Its a thin line though.

Ozone is a stronger oxidizer than Chlorine or Bromine so in actuality the occurance of DBPs are reduced about as good as you can get with Ozone over the use of Chlorine. Higher likely of reaction completness. Also, the DBP's are carcinogenically safer in many cases than Chlorine or Bromine DBP's. For example, an aldehyde or ketone can be produced...keeping in mind that cinnamin and bananas contain aldehydes. Most pesticides and herbacides, on the other hand, contain Chlorine and Bromine compounds.

The truth of the matter is we are swimming in crystal clear water at chlorine levels of only .5PPM. Noone has said anything about chlorine smell. I can't even smell it till its up over 1PPM. I have occassionally let it drift up that high.

I think the key with Ozone is its expensive. We have a large unit and my understanding from the pool supply companies is that I can expect to replace the UV bulb the second its off warranty or within 3 years. They want a lot of money for that bulb...but I think I have found Internet replacements at less than $100. Otherwise, expect to pay $200-$300 or more for a bulb within 3 years.

You will read a lot of negative comments by the BBB crowd on them--I had the same thoughts before hand. However, most of these people have never had an Ozonator on their pool. Mine is only 4 months old though so perhaps their effectiveness weakens like an old bulb but I would say that I am a convert and we have not had a single algae incident. I had all kind of problems trying to do this the other ways by this time.

Ozonation and ionization systems have both been used in many municipal pools, for many years. They are both good for maintaining pool safety, and they will both require maintenance.

As to the failure of your old pool lining, that may have been due to pH being out of control, the hardness maintained too low, or the coating system over the lining was not maintained.

As to the scare story about DBPs, Los Angeles can now tell a story about what chlorine can make in water, and the lion's share of monitored DBPs are produced by chlorine-only systems anyway.

Regardless of the opinions found here, chatboards are a lot further from your reality than professionals in your area. I strongly urge you to start a discussion with a local pool professional, find out what they recommend (even chlorine), what they support, and for how long they have been supporting it.

With all due respect, the link I provided is to a research study (more precisely - a review of research data from multiple studies) completed in Nov. 2007 by the National Exposure Research Laboratory, US Environmental Protection Agency, Athens, GA 30605, USA. [Contact richardson.susan@epa.gov if you have any further questions about its legitimacy]

Just because "the lion's share" of monitored DBP's are produced by chlorine-only systems does not mean that other systems do not produce UNmonitored DBP's which is precisely what this review points out. The few DBP's they do know indicate a potential to be as hazardous if not more so than the chlorine ones.

Ozone has toxicities of its own & from what I understand requires some form of deozonation to protect swimmers. The only form I have been able to find thus far is a carbon filter media which is vulnerable to microbial contamination - there are some studies over at the PubMed database in that regard as well and they are not particularly reassuring. Be careful whose flora you allow in your pool!

We are worried about chemical sensitivity, too, but there are no simple answers to this problem as of yet and the "local pool professional" is not going to be able to give anyone anything more than their personal opinion which will be limited by whatever education & experience (& advertizing hype) they have been exposed to - as well as whatever vested interest they may have in your decision.

This forum actually gives you a better chance of tapping into a wider pool ( ;-) ) of knowledge & experience. True, you cannot blindly trust everything you read or what anyone claims on the net, but that is also true of your "local pool professional".

Personally, I recommend that forum readers look more skeptically at members like lalibs above who post to recommend something having only just registered the day they posted - or like dlzc who post a generic contact rather than having a member page like most members here. Of course they could be legit, but there's a higher probability that they are spamming - especially when they have no posting track-record or one that continually plugs their product.

Ozone has toxicities of its own & from what I understand requires some form of deozonation to protect swimmers.
Thats not true...we don't have anything on our pool to scrub ozone back out of the water.
In addition, Ozone is not stable at all....much of it reacts away with contaminants...however, what is left reverts back to oxygen very quickly. It has a half-life of less than 30 minutes dissolved in water. Much of it though escapes out of the water at the return because it does not have "unlimited" soluability. If it stayed in the water, we wouldn't need to add Chlorine.

Check the EPA's list of carcinogens and there are many more that contain chlorine or bromine than there are alkyl ketones or aldehydes...with the possible exception of benzyl compounds since the aromatic structure tends to stabilize the free electrons of the chlorinated and brominated compounds. The later is what makes up the bulk of the chemical structures of pesticides and herbicides where are nearly all carcinogenic or poisionous to humans.

barco,
I don't profess to be an expert on anything nor do I claim to have all the answers. The abstract says, "Alternative disinfection practices result in drinking water from which extracted organic material is less mutagenic than extracts of chlorinated water. However, the levels of many emerging DBPs are increased by alternative disinfectants (primarily ozone or chloramines) compared to chlorination, and many emerging DBPs are more genotoxic than some of the regulated DBPs."

They didn't say "we think" or "possibly" but stated plainly that they exist. Now there are certainly other issues to consider like what levels do they have to reach to be of concern and perhaps a combination pool would allow the DBP's of both chlorine & ozone to remain lower than either alone thereby making a safer system - I don't know & apparently science doesn't know yet either.

The EPA's list consists of known carcinogens - that doesn't help with the many unknown ones which is the other important statement from the abstract I linked - there are many unknown ("emerging") DBP's.

I have developed an autoimmune thyroid condition. I have a son with Tourette Syndrome, a daughter with elements of dyslexia & hyperactivity, another son with what would be labeled as high functioning atypical autism if we had him formally diagnosed (who, having read the EPA's reports first on mercury & then on dental amalgams, I am pretty darn sure is suffering from mercury poisoning after having had a filling replaced while I was 5 mos pregnant with him. This from the same EPA which just recently lost a court battle & is now required to warn women to avoid getting amalgams while pregnant) and all of us - 5 kids plus me & DH - are struggling with allergies & food intolerances.

We have no significant family history of these issues, so while the vulnerability may be genetic, the trigger is definitely environmental.

Dealing with all that, along with having spent several years researching the hype from all sides of these issues and poring thru medical abstracts & research studies, I am no longer willing or able to gamble that what I don't know won't hurt me - or my kids. I already develop hyper-reactive airways (aka pre-asthma) on high ozone days. I'm sorry, but we are too vulnerable to gamble on this stuff. Judging from the rising numbers of people developing these problems, we are not the only ones.

OK, so this is going to degrade to slamming ozone and ionizer systems based on "extensive review of literature" and "personal health issues".

Sodium bromate has undergone extensive testing by the US-NIH, and it is not a carcinogen. Both potassium bromate and potassium carbonate are carcinogens for particular organisms. And chlorine makes bromate too.

http://coachsci.sdsu.edu/swimming/chlorine/chlorine.htm
... chlorine is no better, and appears to me to be worse.

It is clear you are satisfied with the performance of your chlorine system. The OP had corrosion and liner failure issues with his chlorine system, and got "it wasn't the chlorine system", but not what it could have been from the "chlorine crowd".

Ozone is typically applied prior to the sand filter, and does not survive more than a few mm into the sand. Its purpose is to reactivate whatever *is* the primary disinfectant (commonly bromine to hypobromous). Ozone as a primary disinfectant in a pool is pretty rare, as this is a *lot* of ozone.

Assuming you were interested in facts, rather than whatever you picked up in your travels.

dlzc,
I am not "slamming ozone and ionizer systems". I posted a link to an EPA review of the DBP's of such systems. Arguing individual DBP's rather than addressing the review still leaves this unaddressed, "Alternative disinfection practices result in drinking water from which extracted organic material is less mutagenic than extracts of chlorinated water. However, the levels of many emerging DBPs are increased by alternative disinfectants (primarily ozone or chloramines) compared to chlorination, and many emerging DBPs are more genotoxic than some of the regulated DBPs."

Chlorine may be no better than ozone, but according to the scientists involved in the abstract, it appears to THEM that it COULD BE worse. Now between my education & my experience, I definitely do NOT worship on the altar of science or medicine. I know with certainty that they can be obstinately blind, biased or just plain wrong. However, in this case it appears to be the most solid ground we have to work with.

I'd love to hear your facts - just please have enough respect for my intelligence to present them in a way that gives us more to go on than your say-so.

As requested:
http://ntp-server.niehs.nih.gov/index.cfm?objectid=070EAFCC-E977-3861-AC7327B175...
http://ntp.niehs.nih.gov/index.cfm?objectid=BDC199B6-123F-7908-7BEBC128F6C1ABBE

Bromate is not a carcingoen.

And you ignored the long list of scientific papers that says chorine *is* worse, and worse in pools. Let me supply that again.
http://coachsci.sdsu.edu/swimming/chlorine/chlorine.htm

You don't lean on science or medicine, you lean on politicians (at the EPA). That is not "solid ground". There have been at least two doctors that went on record challenging the US-EPA on their finding against bromate. Also a matter of public record. And the US- National Institutes of Health have shown that bromate is not a carcinogen.

And for what it is worth, ozone is applied to municipal water in several cities in the US for breaking down MIB and geosmin, so that chlorine does not turn them into THM and HAA. Ozone is produced by the roots of marigolds to fight predation, and something very akin to ozone is produced by our white blood cells to fight infection.
http://en.wikipedia.org/wiki/Trioxidane

Now do you want to stick to pools, rather than drinking water? That is where DBPs apply, because it is well known that bromate (for example) is not absorbed through the skin.

gracedunderpressure.

Really, I don't want to defend Ozone as healthyier than Chlorine as its is a loosing...battle. No sanitation method we have does not have ill effects and disadvantages. If there were, we'd all be using it.

Even using ozone requires supplmenting with Chlorine or Bromine so there is no way it can be better for you because we are still usign the "same" chemicals. However, your belief that Ozone is worse as a sanitation method is ill conceived.

Here are the problems with your study.

1. Its a drinking water study -not- a pool study. We don't drink our pool water or shouldn't be. If you are drinking your pool water, I'm here to tell you that the level of THC and THM's (including all the recognized carcinogenics) in your pool are typically 100 times higher than your drinking water using just plain old Chlorine as a sanitation mechanism. These levels are 100 times what this study shows as PPB levels.

2. Drinking water instutions only use Ozone for a short period of time....they do not continuously ozonator like we do in our pool. So that means, ozonated organics later combine with the chlorine and bromine in the water on the water to your faucet or sitting in a VOA jar waiting for analysis. Look at that study and you will see that most of the DBP's mentioned are chlorinated and/or brominated. Ozone is Oxygen only and can't contribute Halogens. These halogens are coming either from cross contamination in the plant, or the analytic results, or they are coming from chlorine and bromine added afterwards to keep the water safe from the plant to your faucett. However, in the case of the pool, this water is continously exposed to ozone which will further break down these DBP's to lower MW aldehydes and ketones or eventually to methanes that gas out of the pool. So unless you are gathering pitchers of your pool water for drinking water of PPB concentrated constutents, you simply are taking something these results out of context.

What I'm trying to describe is illustrated in this study on Pool chlorination and ozonation. https://dspace.lib.cranfield.ac.uk/handle/1826/108

You will see the conclusion that ozonation initially raises THM concentrations but upon further Ozone/UV (about 100 hours), the levels return to the results you get with plain Chlorination. This fact is what you are seeing illustrated with this paper as to drinking water. Unfortunately drinking water is not continuously treated like your pool is. We all would need to use ozone for a total of 100 hours right before we drank it.

Restating the conclusion #9:

9)Ozone-GAC appears to be the most effective treatment for surpressing and THM levels...

You will also take note that if we could use Ozone ONLY and not have any chlorine or bromine in the water, then we would get less THM's and DBP's. Its the chlorine dose rate used in conjunction with the Ozone that is at issue...not the ozone itself.

dlzc,
Sorry to be so dense, but I don't understand why you are going on about bromates - where does that fit into the chlorine-ozone debate? The link about chlorine didn't do anything for me because I already know about the hazards of chlorine to breathing. The report I cited was discussing carcinogenicity of DBP's so ozone may relieve the lung irritation & inflammation, but if its DBP's are going to give us cancer, I think I'd rather have asthma.

Okay, I'm just being facetious. I realize that chlorine's DBP's are carcinogenic as well, but the point is that the study suggests that the emerging DBP's may be worse than the regulated ones.

As far as politics and the EPA - look back at what I said about mercury & my son. It took a court order for them to warn people about the hazards of dental amalgams. They knew this for decades. My son could have been protected - now I get to spend a fortune on treatments for his disrupted metabolism & worry about his ability to have an independent future. Trust me, I am well aware that politics trumps truth over there.

Nevertheless, I need something resembling scientific data to substantiate the claims of ozone being healthier than chlorine as a toxin. A third party independent lab would be ideal, but I'll settle for somebody at least making a pretense at objective collection of data.

barco,
Your link sounds really interesting, but I am getting a "Service Temporarily Unavailable" message so I have yet to be able to look at it. I'll keep trying & get back to you later. Thanks!

Okay, I'm just being facetious. I realize that chlorine's DBP's are carcinogenic as well, but the point is that the study suggests that the emerging DBP's may be worse than the regulated ones.
Possibly...If you plan on ozonating your water and then letting it sit for 3 days with chlorine only and then drinking 8 x 8 ounces glasses of your pool water per day after that. Then, I think maybe you might want to seriously consider the EPA tests that you published. Otherwise---they are meaningless.

Why do you think the EPA has moved to moderate their testing standards towards ozone disinfected water in the first place.

Further, the EPA is somewhat guessing at these chemicals being worse in drinking water. We do not have have human carcinogenic or mutagenic data on every conceivable chemical. However, typically double bonded or oxygenated halogens are MORE poisonous than Halo-only organics compounds....so this is not all that far fetched.

However, I have dealt with lots of EPA chemists and have trained them on our equipment...what they say is not religious. Most of the chemists making the most money and most knowledgeable are NOT working for the government...just a fact. It sounds to me, they just want to start moving towards the monitoring of these other organics in drinking water which they do not currently monitor. Have you emailed this chemist yourself and ask her if she believed pools with ozoneated water are thus also more dangerous than those using chlorination treatment? You should do that.

"Nevertheless, I need something resembling scientific data to substantiate the claims of ozone being healthier than chlorine as a toxin. A third party independent lab would be ideal, but I'll settle for somebody at least making a pretense at objective collection of data."

You want a healty toxin? You are kidding still, right?

As far as the link I provided about pool safety, you seemed to have missed the toxins drawn in through the skin:
"CHLORINE PRODUCT ABSORPTION IN SWIMMERS IS GREATEST VIA THE SKIN"

Sorry if I make you feel more "under pressure", but I have worked at two companies that folded because such unfounded suspicion as you seem to hold as fact, eroded the market.

As to citations, sure:
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=202897
http://toxsci.oxfordjournals.org/cgi/reprint/52/2/162.pdf
... now do you have a citation where chlorine gas was similarly applied?

Try a chemical free system there are 2 great products on the market. I have 14 years of experience running pools with no chemicals.i have to products using the same technology.You will have water in your pool that is like bottled water.

Here is a link that might be useful: htp://www.ecosmartusawest.com

"You want a healty toxin? You are kidding still, right?"

I misspoke or mis-wrote - whatever - leave off the "as a toxin" and you have the gist of my intent. The dermal absorption of chlorine DBP's did not escape my attention - has anyone studied how much if any ozone DBP's get absorbed?

You are not making me feel more "under pressure" - this is just a blip on that radar. You are just making me feel very tired & sad. You would think all of us would be on the same side - humanity. Whatever. I haven't declared war on anyone or anything. I have no ax to grind. I'm sorry that you don't like my suspicion, but in case you missed it, my naive trust led to the damage of my children. I have to protect them as best I can. It is horrifying what people are willing to overlook or ignore when they have money at stake.

Since you mention it, I would like to know more about the companies you have worked for & who you are working for now - are you willing to share? I've told you where I'm coming from - Why are you so defensive of ozone & ionizers? (And bromine?)

I'll look at your info later tonight when things are calmer and I am less distracted.

Oh look, we have another new forum member. What a timely coincidence.

Here is a link that might be useful: EcoSmarte System...

Gee...Did I start this? 8-]

I truly appreciate all the info and discussion.

I have looked at the Ecosmart System. And any other Ozone/Ionizers I can find on the net. I was hoping to get more info to make a decision on which way to go.

Barco and Graceunderpressure, What exactly are you using in your pools?

Try a chemical free system

There is NO chemical Free System !!!!

Many of these system use metals--and claim this is somehow "chemical free". I don't think so. Metals are elements and oxidized as chemicals. The entire field of inorganic chemistry is the study of metals. Metals once dissolved in your Pool ARE DIFFICULT if NOT IMPOSSIBLE to remove. Metals in your body are also BAD. They collect up in your liver and they are just as difficult to get rid of your body as they are from your pool. In fact, they cross the placenta barrier and enter your children.

As a chemist, concerned about the health of my family, I would choose Ozone over a metallic solution any day of the week. In fact, I would choose Chlorine over a metalic solution any day of the week. Ozone is the closest thing to "chemical free"...because its "OXYGEN" and it sanitizes and then reverts back to diatomic oxygen where it mostly escapes back into the atmosphere.

Does the EPA approve the use of Metalic sanitation solutions for your Drinking Water? ABSOLUTELY NOT! In fact, they are forced to test for metals and required to keep metals and inorganics below maximum toxicity limits. WHY -- ask yourself?

I believe that Metal toxicity will be found to be the cause of many permanent illnesses...and nervous system irregularities. We already know about mercury poisioning, lead poisioning and the possibility that aluminum poisioning causes alzeiheimers. You think copper or silver are somehow safe compared to every other metal that will kill you or make you sick? I understand you need copper but we already get plenty.

Think twice.

I have used BBB / chlorine in my first pool. I have used SWCG generation in my first pool. I currenty use Ozone in my pool.

To: graceunderpressure
1) OREC -> Osmonics -> GE... now no longer make their own ozone generators
2) GDT... now not concentrating on ozone contacting

Currently working for a non-ozone ion exchange company. In fact they tend to avoid ozone.

Since finding on bromate
* PCI bought by Wedeco, Wedeco now not operating in the US.
* Trailigaz largely gone.
* Only the Japanese and Ozonia still making a go of it.

To lindamarie:
Sorry about my contribution to the "emotional outburst".

I still strongly recommend you find a local, reputable distributor of such products, and seek their recommendation. They will be your source of warranties, spare parts, and advice. This is a poor place to get such advice, since there are no "belly buttons" that you can hold responsible for bad advice.

barco,
I finally got thru to your link - it was worth the wait. I'm wondering - how come you're sold on ozone rather than UV? Seems like a combo SWG/UV might be better? Also, I thought you were talking before about SWG/ozone combined but now you seem to be just ozone? Would you mind sharing your thinking that got you to this point? (I agree with you about the metals, btw. To hype them as if they are benign is irresponsible. Copper is the most common one - The standard American diet already has an overbalance of copper & the symptoms are there -- and if you've ever bought copper to treat plant disease like fireblight, the warnings about not letting it get into the water supply make you want to just forget about it)

dlzc,
I'm sorry for your difficulties. I looked back over the thread trying to figure out what was making you so antagonistic & I guess it was my swipe at your M.O. following your dismissal of my "scare story". It sounded like an unwarranted sneer with nothing to back it up so I figured you must be pitching something. I was not sobbing in your beer, but trying to explain to you that I have no agenda other than my family's health. I apologize for whatever misunderstanding occurred - I just don't have the time or energy for this.

lindamarie,
I hope this hasn't messed up your thread. It sounds like we are asking the same questions. I do not have a pool yet, but am planning on a build probably at the end of next year. (And we're in the process of setting up a generic Intex pool so that we can get a better feel for the chemistry & make sure we want to have a permanent pool)

My younger sister (31yo) is about to undergo an operation to remove a grapefruit size cyst from her abdomen - looks benign so far, thankfully. She swam competitively during high school. All of the pools in her school district were indoors & chlorinated. I can't help but wonder, you know?

The devil you don't know can be worse than the devil you do know so we're trying to find the path of least risk - known or potential. Haven't been able to find much outside of the EPA here in the US so I'm trying to get a look at what Europe & Australia have been doing since they have apparently been doing a lot more with the alternative sanitizers in their pools.

One point that keeps getting mentioned consistently is to minimize the organic matter that enters the pool as that is what oxidizes into DBP's - so showering before entering the pool will actually minimize the chemicals & toxicity. Someone needs to explain that in some way that kids can understand because when I was a kid, I hated those pool showers (they were always so cold) and couldn't for the life of me figure out why you had to get wet to get into the pool, LOL!

We went with EcoSmarte chemical free system for about a month and a half. I got fed up with trying to be the weekend chemist and realized I didn't buy a pool to add more workload to my already busy world. I had it changed out to a Jandy AquaPure chlorinator salt system. The ppm of the salt in the pool is less than that in your teardrops. We love it.

I still like the idea of a SWCG system in combination with ozone or UV. Looking at this subject I am concerned though with Bromate issue that potentially is a problem with Salt water and Ozone...I only just noticed that looking at this subject from the post earlier about Bromate. So I would need to understand that further.

The thing about it like I said earlier is my ozoneator is still surprising me every day. Its working so much better than most folks are saying/posting and that I had expected. The technology has definetly advanced in the last 10 years. I'm starting to push my chlorine level much lower than 1PPM now, even lower than .5PPM and still seeing no problems. And the water is amazingly clear and clean. I have not swimmed in anything like it...it is the closest I have experienced to swimming in drinking water. So I'm nearly a complete convert from where I was 3 months or 6 months ago. Given the chlorine level is already so low, I'm at the point of why bother with the SWCG.... Thats about the only change that is occuring.

Also I had some problems intially with my install because the PB didn't do the install correctly. I have since fixed those as well. The only problem that I see so far is that Ozone in the pump path as a metal oxidizer makes salt look tame. A spring I have watched in my flow meter is completely rusted in only a few months. Salt is bad but not nearly as corrosive having used it before. Hopefully this will not turn into some unforseen costly repairs. That spring at the rate its going...won't last beyond a year.

Not much difference really between Ozone and UV. Our Ozone generator is actually just a UV germicidal lamp with a vacuum on it. UV is going to excite more than just ozone so you are definetly going to complicate your DBP problem if that is what you are most concerned with since it will create a plethoria more of oxidized/semi-oxidized species besides ozone from the oxygen in the water.

Barco

Please email me privately and tell me which ozoneator unit you are presently using?

barco:
For bromate, look at the links I provided. If you want the politicians' version (that concentrates on postassium bromate testing):
http://www.epa.gov/iris/toxreviews/1002-tr.pdf
People put toxic amounts of bromate in their hair to make it "look better". Unless you drink a gallon or so of your pool / spa water daily, "bromate" will not be an issue for you. Bromate uptake through the skin has been tested and is "non-detect".

Regarding turning off your SWCG system, ozone has a very short half-life in water. You need some primary steriliant in the pool to prevent infection from setting in. Unless your UV-based system is very large, or your pool / spa is very small, ozone will not be your primary sterilant.

In pools, ozone is most commonly applied to the feed into a sand filter, and offgas is released from the top (inlet side) of that filter. The ozone is destroyed a few mm into the sand filter. If you don't have this arrangement, ozone will corrode steel, brass, bronze, copper and more. Metals safe downstream of ozone are: stainless steel, titanium, gold, stuff like that.

The difference between ozone and UV is that ozone provides oxygen to chemcial reactions, ozone acts like a flocculant (making the filter work better), ozone stays in the water a while, ozone works in cloudy water, and UV doesn't. On the other hand, UV doesn't have off gas to worry about, and rarely requires cleaning.

To the OP:
UV-based systems are awfully small for a pool that is large enough to have a gunnite coating. You probably need a corona-discharge system, because of water flow rates and bather loading.

I again urge you to contact your local pool supplier for his / her recommendation. They will provide instruction and warranty for the system they will recommend for a pool of your size. You can find a reputable company by looking at the Better Business Bureau (or your local equivalent).

Our PB installed our Ozone system not me. Its an UltraPure system.

We are using a cartridge filter not a sand/DE filter.

I was originally planning on replacing it with a SWCG, but decided to give it a try. Eventhough its a UV germicidal lamp, it is not having any trouble at all keeping the pool clean and it is acting as the primary sterilizer. In fact, I'm only running it for about 4 hours per day. Half as long as I use to run my SWCG and currently, I am maintaining a chlorine level of 0 to .5 PPM. This concentration is barely indicated on my test kit. I am now down to one Chlorine puck per week. No algae bloom yet.....water is crystal clear. The only disadvantage to that is that I can see all the imperfections on the Stonescape as well as dirt at the bottom of the pool.

If it sounds unbelieveable...so far it has been. The chlorine in my pool water is about the same as your glass of water. The ozone runs for 4 hours in the day, sterilizing the water pre-filter and chlorine is added to the water after treatment. I run the pump for another 3 hours at night without ozone and only filteration and chlorine addition.

How did I miss this thread this summer? Well, found it now while looking for health issues related to DE usage (I will ask about this in another thread and also will post a question asking about a particular brand of product used as a mineral sanitizer). Thank you to everyone who contributed to this thread. I truly believe we need to learn from one another and share what we think will help people even if it is only based on our anecdotal experience. I found if you start talking health issues with the PBs or the folks who sell you all the chemicals they either (1) clam up, (2) Poo-poo your concerns, or (3) run the other way and never get back to you. In any case, their opinion is bound to be, yet again, just another opinion among many and it is unlikely they will speak ill of a product they trying to sell you. But I am hopeful enough to think that there are industry professionals seriously concerned about getting answers too and will support finding better solutions. Until then, the myriad of choices are out there. We need to hear from those who can share more on this topic Some of us are more sensitive physically (and emotionally) to health issues. However, there are enough people on this site so that probably every product and technology out there has been used by somebody here. Everybody can't be right and probably there are pros and cons to each to learn about. I just wish there was more unbiased research and well founded, irrefutable facts upon which to base one's judgment.

So, Lindamarie, what did you finally go with as an alternative/supplemental sanitizer? Barco, have you noticed any other filter, pump or heater issues that might be attributed to the Ozone system similar to the potential damaging affects of SWG? Grace, I can so relate to much of your personal story to be pro-active when it comes to your family's health. Heck, if we know even doctors can be honestly misled by flawed studies or influenced by drug company incentives can we really expect more of people whose income is derived from selling us anything else? Just the way the world is I guess. It's easy to get discouraged as I did for a while when you have so many other things to handle in your life (Oh, yeah--that's how I missed it). Hope you are back on track for getting your yourself and family the pool that should ultimately be a temporary respite of sorts from life's cares.