Ozone and hot tubs - some basics. Part 3 - Long!

[In Canada eh]

ozone's effectiveness doesn't apply (you HAVE to have a residual).
  But, I do not like the implications or claims that manufacturers make that it functions as a sanitizer in hot tubs and then those same groups cannot produce solid test data supporting that claim.

[In Canada eh]

Sorry now I messed up the quote thing,

Are you claiming that ozonators do not work in tubs or just that there is no info that they do?

Another question, since ozone does improve the water quality, can we not assume a short residual?

Sorry about the earlier post and run.

[Vermonter]

In_Canada_eh,

Are you claiming that ozonators do not work in tubs or just that there is no info that they do?

Interesting question - sure you're not an attorney?  I'll say (my opinion), "yes" to both questions.    The reasons for "yes" are based on my own (admittedly, limited) testing, understanding of the use of ozone in aqueous systems and the lack of any published, defensible data from tub manufacturers or ozonator manufacturers (you would think they would publish confirming information on the effectiveness if they actually had it, wouldn't you?).
   

Another question, since ozone does improve the water quality, can we not assume a short residual?

As sort of mentioned in one of my earlier posts, I think that ozone can, and does, function as an oxidizer (especially it is 24/7) and, depending on the degree of tub usage, can certainly contribute to overall tub physicalchemical quality.  It certainly won't hurt and I think it helps.  

However, any residual present either has its oxidative demand totally quenched by the organic / inorganic contaminants in the tub water so the issue of a residual is a moot point or, if not, the residual is too low (my experience) to be measured by a highly sensitive, ozone specific measurement method.

Vermonter

[stuart]

Wow! You are quite an asset to the board Vermonter...Thanks for the input!

I do have a couple of questions for you because it sounds like you know your stuff.

1. If ozone is an effective sanitizer and kills bacteria then being an airborne oxidizer what is to keep it from wiping out the good bacteria in our lungs? Considering the fact that most spas "dump" the ozone into the bather load while it is still active I would think that it could actually be a health risk?

To my knowledge the EPA regulates home air purifiers to the amount of ozone they put out and it's a whole lot less than spas. Why do they regulate that?

Here is an ugly scenario if this works like I think it does...in most spas ozone collects in the trapped air between the water and the cover, you open the cover and breath the ozone into your lungs depleting the stores of good bacteria that fights of disease. Then you get into the spa and sweat around a pint of fluid that breeds bad bacteria in the over 100 degree water and when you turn the jets on you make some of that airborne and breath it in causing respiratory issues.

I think that this is a problem with spas that has never been addressed

2. Second Question is more of a statement…. As everyone knows, we sell several brands of spas. Giving all of our wet models the same attention the difference in water quality in the D1 line is very noticeably better then the rest without added sanitizers. They don’t filter more, they don’t have a frog system but they stay really clean. It is my belief that this is because of the fact that they do more than 98% of the ozone in the plumbing and not the bather load keeping the ozone in contact with the water longer than just about any other manufacture.

Your input here would be greatly appreciated!!

BTW, here is a link to the EPA site talking about O3
http://www.epa.gov/iaq/pubs/ozonegen.html#table%201

[Stemay]

Wow!  What an education!  Not sure I understood it all (or really need to).  But, i have a much better idea of why I absolutely need to add dichlor and not just depend on the Ozonoator and Nature 2 cartridge to do all the work in between my weekly shock (which is all the dealer told me would be required).  

Tonight I started dichlor!  Looking forward to the water staying clear all the time (once i've got the routine down pat) and also after reading about that the ozonator is not a magic bullet, I feel so much better that I will be effectively killing bacteria for real.

Thanks!

[In Canada eh]

Vermonter

Are you familiar with Wallace and Tiernan amperometric residual analyzers.
http://www.usfilter.com/en/Product+Lines/Wallace_and_Tiernan_Products/Wallace_and_Tiernan_Products/wallaceandtiernan_product_Depolox+3+Plus.htm
Its a massive link but they make a very good product.

I know that we can't ask a tub owner to have this installed but, I wonder if one of the ozone makers (Delzone or Jed) has ever used one.  It may be the test that would or would not prove ozones use in tubs

[In Canada eh]

In_Canada_eh,


Interesting question - sure you're not an attorney?  I'

Positive on that, I am very happy just being a toolmaker and mechanic

Once again Sir/Madame it is an honor to have you contributing to this forum

[Vermonter]

1. If ozone is an effective sanitizer and kills bacteria then being an airborne oxidizer what is to keep it from wiping out the good bacteria in our lungs? Considering the fact that most spas "dump" the ozone into the bather load while it is still active I would think that it could actually be a health risk?

Hi stuart,

Tub manufacturers, and, I believe, ozonator manufacturers (for hot tubs),  are required to have their units tested to national standards to ensure that the offgas production of a functioning unit does not exceed safety standards - at least if they want to be able to list their tubs as, I believe, UL (perhaps it is OSHA) approved.  As I recall (it's been some time since I looked at this) the whole tub is placed ina 10'x10'x10' closed room and three ambient (gaseous / air) monitors are placed in the room.  Again, as I recall, one is in the equipment cabinet, one in the area immediately above the tub and one somewhere else in the enclosure.  The ozonator and tub are turned on and I believe that the test period (ozonator running continuously) is either 8 hours or 24 hours and none of the readings at any of the monitors / sensors can exceed the OSHA (?) established levels.  

Your link also points out that if ambient ozone levels are at or below the established safety limits that no effective "killing" of microbes would occur.  So, I am personally comfortable in not being concerned about ozone off-gas from a hot tub being high enough to do me any harm.

To my knowledge the EPA regulates home air purifiers to the amount of ozone they put out and it's a whole lot less than spas. Why do they regulate that?  

Your link (and there are numerous other good authoritative links on this subject) points out the potential health effects of ozone at "unsafe" levels as being:
Potential risk of experiencing:

Decreases in lung function

Aggravation of asthma

Throat irritation and cough

Chest pain and shortness of breath

Inflammation of lung tissue

Higher susceptibility to respiratory infection

So, as with many other airborne chemicals, regulatory agencies have established both short-term and long-term maximum levels.  This has been done with gaseous (airborne) ozone.

Here is an ugly scenario if this works like I think it does...in most spas ozone collects in the trapped air between the water and the cover, you open the cover and breath the ozone into your lungs depleting the stores of good bacteria that fights of disease. Then you get into the spa and sweat around a pint of fluid that breeds bad bacteria in the over 100 degree water and when you turn the jets on you make some of that airborne and breath it in causing respiratory issues.

This is pretty much covered above - tubs are designed so that they meet national health / safety standards with respect to their production of off-gas which would then become the airborne ozone you are referring to.

I think that this is a problem with spas that has never been addressed

2. Second Question is more of a statement�. As everyone knows, we sell several brands of spas. Giving all of our wet models the same attention the difference in water quality in the D1 line is very noticeably better then the rest without added sanitizers. They don�t filter more, they don�t have a frog system but they stay really clean. It is my belief that this is because of the fact that they do more than 98% of the ozone in the plumbing and not the bather load keeping the ozone in contact with the water longer than just about any other manufacture.  

As pointed out in some of my earlier posts in this and related threads, while I strongly do NOT believe that there iis any defensible data to indicate that ozonators on hot tubs are effective in controlling microbes, I do believe that ozone (are D1's 24/7? for ozone) can and will result in physical/ chemical benefits to the hot tub water. That opinion is based not only an understanding of what ozone is and how it works, but also on the testimony of you and many others who state emphatically that they see an improved water quality when ozonators are used.  Would all ozonators cause an improvement?  Probably not - this gets into design considerations such as ozonator output, water temp, contact chamber design, amount of mixing of the bubbles with the water, etc.

Best,

Vermonter

[stuart]

This is pretty much covered above - tubs are designed so that they meet national health / safety standards with respect to their production of off-gas which would then become the airborne ozone you are referring to.
 
I think that this is a problem with spas that has never been addressed

Lets not kid ourselves....Most spa manufactures DO NOT care if they meet national health / safety standards nor is there any spa police out there checking. I think you would be surprised at how many of the over 200 manufactures have never been tested and I would bet less then 20 of them actually comply. Some claim UL because the equipment pack is UL but the spa is not. I will just about guarantee that if you buy a spa off the Internet it will not have met many of these standards.

Besides, UL really has not addressed this well, neither has ETL and I personally believe it is a bigger problem than we think. It's my opinion that many people get a cough or sinus infection after setting in the spa the night before and blame it on weather or something else when it was the spa all along.

I love what I do and truly appreciate the benefits of what our products do for customers and their families but really wish we would get some safety regulations that are realistic and enforceable.

...and your correct, this and other things have never been addressed.

BTW, to my knowledge ozone manufactures are not held to a standard of how much ozone the put into a spa.  

Somewhere in my Metrology days I remember a home test you could do to test ozone...I will try to look it up and post it.

[Mendocino101]

Wow!  What an education!  Not sure I understood it all (or really need to).  But, i have a much better idea of why I absolutely need to add dichlor and not just depend on the Ozonoator and Nature 2 cartridge to do all the work in between my weekly shock (which is all the dealer told me would be required).  

Thanks!

This is exactly what I mentioned earlier along with Steve....some dealers want to try and convince someone they have almost magic water in their spas and it will be sanitizer free....simply untrue but with the right and regular care it can be very simple and safe....

[Vermonter]

This is exactly what I mentioned earlier along with Steve....some dealers want to try and convince someone they have almost magic water in their spas and it will be sanitizer free....simply untrue but with the right and regular care it can be very simple and safe....

I agree - 100%!

Vermonter

[Vermonter]

Your right ozone and crypto CT is I believe 2.5

That value of 2.5 may actually be low, depending on what the % disinfection goal is.  The January 5, 2006 Federal Register (40 CFR Parts 9, 141 and 142 dealing with the Final LT2 rule whic is aimed at Cryptosporidium in drinking water) lists, in Tble IV.D-3, CT values for Ozone at various water temps.  For 30'C (well below hot tub temps), they give a CT of 4.7 for a 3-log (99.9%) reduction in Crypto.  

But, whether it is 2.5 or 4.7 or some other number, let's look at what that means in a hot tub:  

If, for the sake of discussion, we assume that you don't have an ozone residual of any level being able to be produced and maintained in the hot tub itself, you are forced to rely on the dissolved ozone residual that would be present in the contact chamber.  Let's say that you have a residence time of 1 minute (this is likely longer than most, if not all tubs, actually have), this means that for the discrete parcel of water that you have injected ozone into, ithat parcel of water would stay in the contact chamber for 1 full minute.  

Since I believe some of the slower circulation / injection tubing pumps are pumping at 4 - 6 gpm (as in HotSpring), then the volume of water in the tubing would have to b3 4 - 6 gallons to get that 1 minute of contact time.  This isn't likely to be the case (volume would be a fraction of that within the 10 feet or so of tubing), but, even if it was the case, you would then have to have an ozonator capble of putting 4.7 mg/L of dissolved ozone into the water AND assume no decay or half-life drop for one full minute.

No testing of mine and no reports that I have EVER seen have been able to claim a dissolved ozone residual of any level much less up in the range of 4.7 mg/L.  And, even if you could have that in the contact chamber, to be "safe" you would want something close to that in the hot tub itself since you are not able to be ensured that every parcel of water in the tub goes through the contact chamber on a regular basis.

Luckily, the chances of Crypto being present in hot tubs should be relatively small and, unless you ingest them, you won't have a problem (i.e. don't drink you hot tub water!!).

Vermonter