Ozone and hot tubs - some basics. Part 1 - long!

[Vermonter]

I have followed, with interest, a few of the recent threads that deal with the general subject of "ozone".

I guess it is appropriate for my first post on this forum to focus on ozone - a topic that I have nearly 30 years of experience with ranging from 3 million gallon per day high purity water systems (semiconductor) to drinking water systems many  times that size to table-top carafes treating a liter at a time to hot tubs.  Regarding hot tubs, one of my first posts on the rhtubs.com site concerned ozone - and, over the years, there have been several dozen on that site that followed that original post.

For this post, I wanted to not get into specific applications of ozone to hot tubs; what brand does or doesn't have a contactor, etc.  Rather, I thought I would go through the basics of ozone - both as an oxidizer and as a sanitizer / disinfectant.

I should say that the following represents my opinion - backed by a considerable amount of experience and actual testing of ozone in hot tubs.

General:

First, ozone, like chlorine and bromine, is both an oxidizer and a sanitizer / disinfectant.  Ozone functions first as an oxidant and secondarily as a sanitizer (I will use the term sanitizer vs. disinfectant; while ozone is a disinfectant, its use, in hot tubs, would, under optimum conditions, function as a sanitizer).

Ozone as an Oxidizer:

An oxidizer serves to "oxidize" or break down both organic and inorganic "contaminants" in your spa's water.  If you use chlorine, some of the more common contaminants are chloramines - shocking with chlorine or MPS will effectively break down those compounds; theoretically, ozone would do the same.  Other contaminants are from body waste (sweat, skin flakes, etc.), natural contaminants (pollen, insects, dust, etc.), contaminants in your water (both organic carbon as well as inorganic species such as iron, manganese, etc.).  Oxidation breaks these contaminants down into simpler compounds.  In the case of organics, the ultimate breakdown product is likely to be carbon dioxide or some simple form of organic acid.  In the case of inorganics, it will be some oxidized form of the inorganic (i.e. a metal oxide).  

If you have a tub with an ozonator installed and, if you have some "clear" tubing downstream of the Mazzei injector site, take a look at the tubing after a few weeks or months of use - most likely it will be reddish colored.   That is the result of the ozone oxidizing the iron in your water from the reduced, ferrous state to the oxidized, ferric (rust) state.  The fact that you see this immediately downstream of you ozonator is a visual representation of what I said above - oxidizers, in this case, ozone, functions first as an oxidizer (hence the color immediately after the ozone is introduced).

Part 2 continues with ozone as a sanitizer....and more!

Best,

Vermonter

[Chas]

Welcome! It's good to see a post from you here.

[Bill_Stevenson]

I would like to echo Chas's welcome.  You are a legend around here.  Thanks for posting.

Bill

[tony]

Vermonter

How very nice to see you around again.  Its been a long time.  Hope life's been treating you well.

tony

[Vinny]

Vermonter

Welcome!!

What a way to start posting here!

Thanks for the info.

[Vermonter]

To all -  Doc, Chas, Vinny, tony, Bill, Steve, Lori...and others familiar with me from rhtubs.com forum- thanks for the welcome.  I expect to be back and forth on both - as time allows.

Nice to hear from all of you.

Vermonter
P.S.  Beware the Patriots!!!!!!!

[Gomboman]

Wow, this is an honor. We have been refering folks to your chlorine bible at rhtubs for over two years. Thanks so much for stopping by. How did you hear about us?

[Stemay]

Can't wait for part 2!!!!!!!

[Vermonter]

Stemay,

"Parts" 1, 2 and 3 were all posted within a few minutes of each other (too long to fit in one post or even two; it was kicked back).  Just search for the same "Ozone and hot tubs..." title with different "parts".  I guess I should have had all in one thread with the second and third being my own "replies".  Next time...

Vermonter

[hottubdan]

So, what about the claims of Nature2, ozone and MPS being a sanitizing system using chlorine only at start up?  Now EPA registered.

[East_TX_Spa]

If you have a tub with an ozonator installed and, if you have some "clear" tubing downstream of the Mazzei injector site, take a look at the tubing after a few weeks or months of use - most likely it will be reddish colored.

Vermonter

For illustrative purposes in this highly informative post.

Terminator

[Vermonter]

So, what about the claims of Nature2, ozone and MPS being a sanitizing system using chlorine only at start up?  Now EPA registered.

HTD,

Before we get into a more general discussion, do you know if Nature2 for Spas is EPA registered or is just Nature2 for pools?  If the spa version is, do you have a reference or link - or an EPA registration #?   I did a quick search and only found the pool version (#67712-1).

In some respects, the answer won't matter, but I'm curious as to what is registered and what isn't.

Thanks,

Vermonter

[Vermonter]

For illustrative purposes in this highly informative post.

Terminator

Great Photo Terminator!

Nice choice on spas - looks familiar!  I would guess you are on well water, but, depending on how old your spa is, perhaps not.  Were the pumps on when you took this picture?

Check out (unscrew) the diffuser plate for the heater return /  ozonator line in the bottom of your tub.  You will probably see some discoloration there, although much, much less than what you see on the tubing.  This is another "visual" indication that most of the action of any ozone produced doesn't make it to the end of the "contact chamber" much less the tub itself.

Thanks,

Vermonter

[Dr. Spa™ Ret.]

EPA Establishment No. 067712-FL-001

[Chas]

Hey Andy,

I want to buy a PWC. I want a fast one - I'm watching Craigslist, Ebay and local papers. Know of any good deals?