I am writing to point out errors and statements which require clarification in the article entitled Ozone's Partners in the February 1997 issue of Aqua.

First, it is implied that ultraviolet ozonators are inferior to corona discharge systems as in this excerpt from the sidebar entitled Ozone's Origins:

"The corona converts O2 to O3. The amount of O3 created depends on how much current is used and the quality of the feed gas. Generally, it's at least 10 times the amount UV units produces."

This statement is meaningless because it does not reference any base line while implying UV units can produce only one-tenth the output of a corona discharge unit. In fact, in terms of total output, UV units are capable of producing up to 1.25 lbs.-O3/day. Concentrations of ozone will be less (although UV units are capable of producing concentrations up to .9 percent) than typically produced by a corona discharge unit with properly treated air, but units with properly treated air are never found on spas (oxygen concentrators or regenerative air dryers are required). Desiccant dryers will saturate rapidly, resulting in reduced output and the formation of nitric acid - a fact which is rarely mentioned.

Second, in the main body of the article, the terminology again denigrates UV technology by stating that UV technology uses a "small bulb" to generate ozone (implying low outputs) while "sophisticated CD systems" generate high concentrations of ozone. The initial reference is again meaningless because the technologies are different, bulb size varies, and modular UV systems are available which produce up to 1.25 lbs.-O3/day. Additionally, UV technology is not as simple as portrayed, hence the reason so many manufacturers have had to abandon UV production. Finally, the fact that the added "sophistication" of CD systems also adds increased complexity, decreased reliability, and failure modes which can damage a system is ignored.

Please contact me if you have any questions. We would appreciate the opportunity to provide a balanced portrayal of the capabilities of ultraviolet ozonators.

Best Regards,

Ronald E. Brook Vice President, Engineering

PROZONE INTERNATIONAL pH: (256) 539-4570 HUNTSVILLE AL 35802 FX: (205) 539-4225

TO:
FROM: Ronald Brook OF: Pool & Spa News
DATE: 3 Mar 97
FAX: (213) 383-1152
PAGES: 1

I have just completed reading The Ozone Distinction in the February 26, 1997 issue of Pool & Spa News. There are several areas in which I feel the capabilities of vacuum-ultraviolet (185 nm) ozonators were not accurately portrayed, especially with regard to use on pools. Prozone has been manufacturing vacuum-ultraviolet (VUV) ozonators since 1977 for pool and spa use domestically and internationally. In that time we have supplied VUV units for over 4,000 commercial pools and 300,000 spas. Therefore, we would like to set the record straight on the use of VUV units in these applications (in a future article if possible).

The second area, which is equally important, is the portrayal of ozone as a disinfectant. Approaching pool and spa applications in this way has been a disaster. Ozone should be viewed as an oxidizer only in the pool and spa environment. Chlorine acts as the primary sanitizer. This fact cannot be overemphasized and the term alternative sanitizer should be eliminated from trade journals. A common rule of thumb is that 90 percent of chlorine's function is oxidation. The use of ozone reduces this load by oxidizing chloramines and allows chlorine to act more effectively as a sanitizer. Because it is not practical to develop ozone residuals in pools or spas, the term sanitizer is incorrect, misleading, and ill-advised. The DIN Standard is a failed method of promoting the use of corona discharge units.

Following are the areas in which the article fell short:

1. ALTERNATIVE SANITIZER: The NSPI guidelines referenced in the sidebar entitled the "State of Ozone" and the article are written around the idea that ozone is a sanitizer. While this is correct in some applications, it is incorrect in the pool and spa environment. In these applications, ozone functions as an oxidizer. Chlorine acts as the primary sanitizer and ozone as the primary oxidizer.

2. ULTRAVIOLET OZONE GENERATORS: The article states that VUV units are most commonly used in residential spas where the bather load is small and manageable. This statement contradicts several articles which have appeared in your magazine and elsewhere. In general, water in spa has high levels of organic loading from bathers (less water volume per bather), faster chemistry, high temperatures (which are more conducive to bacterial growth), chemical dosage sensitivity, and low total reserves of chemical (i.e. chlorine, bromine) sanitizer. When compared to a pool, spa water is much more difficult to treat. In fact, VUV ozonators are easily scaled-up and can handle commercial and residential pools without problems (and as Prozone has proved since 1977) and at lower cost. The fact of the matter is, VUV units are typically installed with a bypass in which only a fraction of the water is ozonated at any given time. This allows organic loading to be overcome and adequate ozone dosages achieved. The whole pool is not ozonated at once. Size is misrepresented as being a key factor in the ability PROZONE INTERNATIONAL PH: (205) 539-4570 HUNTSVILLE AL 35802 FX: (205) 539-4225

TO: Anne Baye Ericksen
FROM: Ronald Brook
OF: Pool & Spa News
DATE: 3 Mar 97
FAX: (213) 383-1152
PAGES: 1

to provide ozonation (again, spa water has higher loading per gallon than pool water). The notion that VUV ozonators will not work on pools is wrong all the way around. The statements regarding ozone conversion in the lamp chamber are also not accurate. VUV generators produce more ozone with decreasing concentration at high flow rates. Low flow rates produce higher concentrations and lower outputs. Flow rates do not affect the conversion process because it is instantaneous (remember, photon velocity is 186,000 miles per second).

3. CORONA DISCHARGE: This section starts off by endorsing CD units as the selection of choice for commercial pools and spas. Prozone has thousands of successful commercial installations. I would venture to say that corona machines are preferred by corona manufacturers and their paid representatives in these applications. In this country they represent a small fraction of installations as compared to VUV ozonators.

Finally, I feel your magazine is doing the industry a disservice by appearing to limit the use of VUV generators to residential pools and spas. Corona installations typically cost more for commercial installations, are more difficult to maintain, and contrary to advertising are not devices which will operate perpetually. A typical warranty for a CD unit is one year and often does not include the dielectric. Dielectrics do degrade over time and reduce CD unit outputs (a fact rarely mentioned). Prozone warranties all units for two years and the lamps are rated for 20,000 hours with less than a 20 percent loss in output.

Please do not penalize responsible VUV manufacturers with misinformation such as that which appeared in your article. It almost always comes from people who are not experts in VUV technology (Dr. Rice is a corona consultant, DEL Industries has never built a VUV unit which comes close to the quality of unit Prozone provides, Doctors Hartwig and Osinski are not knowledgeable on VUV systems) and is based on old research papers which are no longer valid.

I look forward to discussing these issues with you.

Best Regards,

Ronald L. Barnes cc: Jules Field President and CEO