Ozone - The Sale pitch

[Absolut]

Hi.

Thought you guys should read this too.

I hope Vermonter doesn't mind.
This is copied from:
http://www.rhtubs.com/cgi-bin/bbs/config.pl?read=37337

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Hi Soundguy!

You raise a lot of questions. I'll try to get to all of them, but I'll only answer one in this post (too late to get to all of them...). Hopefully more answers and shorter answers tomorrow...

1) What is the purpose of an ozone generator? Do I need one?

I hate to think of the lines of posting I have already made on this subject - and I hate even more to think of the confusion that still is out there about ozone.

Obviously, the purpose of an ozone generator (either a UV based ozonator or a CD based ozonator) is to produce ozone. But why do you want ozone?

Well, the answer is simple - ozone is both an very powerful oxidizer and a very powerful sanitizer. Optimal hot tub maintenance needs both an oxidizer and sanitizer so, at first glance, ozone would seem ideal.

As an oxidizer it can theoretically serve in much the same function as would using both a "routine" and a "shock" dose of chlorine or MPS (non-chlorine shock). And, theoretically, since it is being continually produced in most spa-ozonator systems, there is a school of thought that says it is constantly oxidizing organic and inorganic wastes that result from the use of a spa and, therefore, the need to perform a more traditional "shock" is reduced or eliminated. There is a flaw in that theory - and I'll come back to that.

From a sanitizing standpoint ozone is documentably far more effective than chlorine, bromine, iodine, peroxide - pretty much any other sanitizer/disinfectant you can think of (except fluorine).

But, as with any sanitizer, the effectiveness against any given microorganism is based upon a standard "term" called "CT". CT stands for "Concentration (of the sanitizer in mg/L) x Time (the contact time - expressed in minutes). The CT value is a fixed value for any specific microorganism using any given sanitizer. The chlorine CT value for E. coli is different than for Pseudomonas aeruginosa which is different from Bacillus subtillus. And the CT for each of those is different for chlorine vs. bromine vs. ozone, etc.

Theoretically, if a bug has a chlorine CT value of 1.0 then you can achieve that by having 10 ppm (mg/L) of chlorine in contact with the bug for 0.1 minutes (10 x 0.1 = 1) or by having 1 ppm of chlorine in contact with the bug for 1.0 minutes (1.0 x 1.0 = 1) or by having 0.1 ppm of chlorine in contact for 10 minutes (0.1 x 10 = 1) - or any combination that multiplies out to "1.0".

A bit confusing, perhaps, but the basic thing to get out of this is that for any "bug" and for any sanitizer you have to have some level of "C" and some duration of contact ("T") at that level - otherwise the multiplicative product of C x T will be "0" and "0" won't kill anything.

The problem with ozone in "factory original" spas is that the "C" of ozone that is obtained is essentially "0" or perhaps is "0". I have been unable to measure a true dissolved ozone residual (the form of ozone you have to have) in either the contact chamber or the main tub water on several types of spas that I have tested. Communication with a very large (largest) tub manufacturer and with the largest manufacturer of ozone gnerators used as factory installed ozonators have confirmed that it is "unlikely" to get a measureable value of ozone on any factory installed system.

So, if the "C" is essentially "0" then the "T" has to be very, very long or you won't have an effective CT value.

Part II below(The post was to long)

[Absolut]

This leads into the second problem of ozone - namely, that its ability to generate and maintain a residual concentration in hot tubs is, unfortunately, practially "0". Since the "T" refers to the contact time at any given concentration, if you can't maintain a residual then you don't have any "T" working for you.

The half-life of ozone (ozone decomposes rapidly - unlike chlorine or bromine, etc.) at about 70'F in absolutely pure (a million times "purer" than drinking water) is reported to be 22 minutes. The half life in spa water is reported to be anywhere from less than a minute to several minutes. The contaminants, chemicals and high temperatures present in hot tub water all work against the ability for ozone to either dissolve in the water and/or to stay as a residual.

So, as with the "C" part of the equation, the "T" part is also essentially "0" - and the "CT" produced in a normal hot tub is therfore so low that the killing efficacy is essentially zero.

Another factor is that ozone, just as is chlorine or any of the halogen/oxidizer based sanitizers, is FIRSTLY an oxidizer and SECONDARILY a sanitizer. That means that if you do get any residual in the water, the oxidative demand exerted by the organic and inorganic wastes in the tub water will preferentially use up the ozone prior to its being able to exert a sanitizing effect.

So, you are pretty much fighting a losing battle - not only do standard ozone generators not put enough ozone into the dissolved form (the only effective killing form - any ozone that is contained in bubbles floating through the tub water are inefeective at killing microorganisms) to kill bugs and but also any of the dissolved ozone produced is likely to be consumed in oxidative reactions and not have the opportunity to kill microorganisms.

This goes back to that "flaw" I mentioned at the top of the post. While ozone can theoretically offer continuous destruction of organic and inorganic waste (and chloramines if you supplement ozone with chlorine) the level of ozone is probably not sufficient to enable you to eliminate the traditional shock.

So, why don't manufacturers use more powerful generators and get enough ozone into solution so that it will be effective? The answer is that if more powerful generators are used, the amount of gaseous ozone released from the tub (only 1 to perhaps 5% of the ozone gas produced goes into solution, the rest off-gases in the bubbles that rise to the tub of your tub) would exceed Federally mandated levels and could potentially have toxic effects on humans (ozone is heavier than air and would tend to collect at the tub). I personally think that this is overplayed if you have an outside tub, but the regulations are there and the last thing a tub manufacturer wants is to have a tub that is deemed "unsafe".

I posted awhile back that Dell had st arted manufacturing/testing of a higher output generator that incoroporated and "ozone destruct" feature that would elminate much of the off-gas ozone, but I have not seen any reports on how well that has worked or even if it is available at this time.

Long-winded, as usual, but I'm trying to be thorough...sorry.

The bottom line for me regarding ozone is:
1) Ozone has tremendous potential both as a hot tub sanitizer and a hot tub oxidizer.
2) At present, ozone generators do not allow sufficient production and transfer of ozone into the dissolved (aqueous) form to allow it to achieve its potential or to be effective as a sanitizer.
3) The inability to maintain a residual in the main hot tub means that any ozone use has to also involve a primary sanitizer (such as chlorine or bromine) to assure you of a microbiologically safe tub.

Enough for now - and I expect there may be some questions or debate on some of this...but that's what this forum is all about.

Do I have ozone in my tub? Yes. Would I buy a tub with ozone again? Probably. Does this make sense, based on the foregoing? Nope - not at all!

Why would I buy it? I really don't have a sound reason. Perhaps because I like gimics. Perhaps because I fundamentally believe in ozone and its application as a water sanitizer and feel that it may add some oxidative value to my tub despite empirical test results. Perhaps because it allows me to test various ideas I have to optimize my ozone performance. And...watching bubbles in my tub is a lot of fun!! (No, Ken, "Bubbles" is not my wife's name!).

Vermonter

[spahappy]

I've read this 3 times and all I can say is WOW. I could never fit that into my sales pitch! lol.
                              Spahappy

[Dr. Spa™ Ret.]

Actually, I think I'm the one that would mind :-) . It's from my board, and I have the copyright........ Ummmmm, wyh didnt you respond to Vermonters post over there (he doesn't post here).?

Everything you say is true, and I agree with. The biggest problem in the "industry" is that salesmen simply don't know, don't understand, and are simply "selling" as their taught to.

Oh, one thing I disagree with, I wouldn't buy an ozonator :-)

Now, you wont mind if I borrow some of your post for a new site I'm working on will you?  

[Starlight]

I too purchased one.  Why?
Well I guess for some of the same reasons outlined by Vermonter.  It will give me a chance to experiment and determine if the empirical reports of reduced sanitizer usage are true.  I have access to some equipment that will help me determine if ozone has had any impact on some tracer compounds (not bugs) I might set up in a separate experimental tank.  At worst, I'm out a few hundred dollars and some time to learn this.  I do believe that ozone COULD eventually be developed into something that has measurable beneficial effects in spa water.  It is such a powerful oxidizer that the CT values are likely to be lower compared with those for chlorine (though just a guess on my part).  Plus, it can oxidize compounds beyond what chlorine is capable of doing thereby helping keep the tub cleaner and chlorine available for sanitizing.  I don't know if this generation of ozone generator and associated injection engineering is sufficiently good to make much of an impact, but I'm willing to experiment and find out.

Starlight

[Shut_Down_Stranger]

Ozone is a powerful oxidizer. -- absolutely...
Ozone is a powerfule sanitizer (disinfectant) - absolutely

From a water treatment perspective, ozone in considered a primary disinfectant

CT is a measure of the amount of disinfectant residual and contact times needed to kill microorgansims. - absolutley

CT values for ozone are very small.
chlorine is higher
bromine is higher yet.

Ozone, because it is so reactive will be consumed berfore a measurable residual is obtained.

Use of ozone will reduce the amount of chlorine / bromine that is required and allow the water to maintain a more stable residual.  

Chlorine and bromine can be used a a primary disinfectant, but because they will maintain a residual concentration (last in water) also can act as a secondary disinfectant. It is necessary to maintain a residual in your spa so microrganisms do not make you ill.  

[Shut_Down_Stranger]

This goes back to that "flaw" I mentioned at the top of the post. While ozone can theoretically offer continuous destruction of organic and inorganic waste (and chloramines if you supplement ozone with chlorine) the level of ozone is probably not sufficient to enable you to eliminate the traditional shock.

Vermonter

The above statment is not correct  Chloramines are formed when ammonia is added to water contains a chlorine residual. Chloramines are a very weak disinfectant, but do not form the amount of undesirable disinfection by products (groups of compounds collectively known as trihalomethanes THM's and haloacetic acids (HAA's)) that are regulated by the government for drinking water consumption.

inorganic waste is not consumed by any disinfectant. Inorganic compounds may be oxidized and captured by the filter, but distruction does not occur.

[Absolut]

Doc

"Actually, I think I'm the one that would mind  . It's from my board, and I have the copyright........
Ummmmm, wyh didnt you respond to Vermonters post over there (he doesn't post here).?

Everything you say is true, and I agree with. The biggest problem in the "industry" is that salesmen simply don't know, don't understand, and are simply "selling" as their taught to."

OK, sorry.., actually I didn't reply to his post, all is Vermonters word copied from your board.

"Oh, one thing I disagree with, I wouldn't buy an ozonator"

Neither did I.

"Now, you wont mind if I borrow some of your post for a new site I'm working on will you?"

It's Vermonters post and as you said, you have the copyright.

/Absolut

 

[Dr. Spa™ Ret.]

Shut_Down_Stranger, as I understand it, the breakdown of some organic wastes creates ammonia which then combones with the chlorine to form chloramines.

Absolut, I'm just funnin with ya.

[Shut_Down_Stranger]

I can state that for most salespeople, the above concepts are not properly taught.

However, that is one of the things that make a forum such as this a good research tool. Others may know the issues.

[Shut_Down_Stranger]

Shut_Down_Stranger, as I understand it, the breakdown of some organic wastes creates ammonia which then combines with the chlorine to form chloramines.

That would only occur if you were filling your tub with  wastewater, as the amount of organic nitrogen that would be formed would not be sufficient to change the free chlorine residual to a total chlorine residual.

[empolgation]

Thar's some educated folk on this thread...

So how does length of the contact chamber come into play? Is it insignificant?

Does it make a difference if the ozonator is running 24/7 with the circ pump versus only when the jet pumps are on?

[CalicoskiesNC]

Sounds like the ozonators being installed on current tubs do not do much of anything.  Why then spend the $200?  I'm thinking of just cancelling mine and making due with chems.  Also, was wondering if you can purchase the cd ozone from Sundance and aftermarket install yourself on a Jacuzzi?  Does that void your warranty?  Are the systems compatible?  Will any ozone system work on any tub?  

My Jacuzzi dealer only uses the UV ozone now, said he had very high failure rates on the cd units.  

[Shut_Down_Stranger]

Thar's some educated folk on this thread...

So how does length of the contact chamber come into play? Is it insignificant?

Does it make a difference if the ozonator is running 24/7 with the circ pump versus only when the jet pumps are on?

Yes, having a contact chamber does make a difference because you are trying to dissolve a gas into water. The length of the contact chamber is not as improtant as the time in the contact chamber. The desing of the inductor is important as well. The Massi inductor is generally recognized as an effective design.

Because ozone is a strong oxidant, some spa makers will turn it off when the large pumps come on.