uv sterelizer
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uv sterilizer
uv sterilizer
I have been using one for years in my reef.I purchased it to help protect against disease,and to promote cleaner,clearer water.It is hard to say if it actually does its intended purpose regarding disease,but it does help with water conditions.Some will swear by them,while others think they are worthless.I see no reason not to use the one you purchased.It is probably something you will have to try for yourself,and then decide if it is worth keeping.
uv sterilizer
I have been using one for years in my reef.I purchased it to help protect against disease,and to promote cleaner,clearer water.It is hard to say if it actually does its intended purpose regarding disease,but it does help with water conditions.Some will swear by them,while others think they are worthless.I see no reason not to use the one you purchased.It is probably something you will have to try for yourself,and then decide if it is worth keeping.
I see no reason to add one to my tank. I don't think it would do anything useful. My fish are never sick that I can tell and I do not think it will help with water quality unless killing suspended bacteria or phytoplankton are a goal.
UV sterilizers do produce small amounts of ozone which increases oxidation of organics,dissolved oxygen,skimmer production. The argument against them is that they indiscriminately kill micro organisms. That being said, your sterilizer will only be able to aid or kill whatever passes through it. It is highly unlikely that your sterilizer would be able to "sterilize your tank", which is a good thing. I personally prefer ozone generators for this job only they do it better. I believe sterilizers have their place but should be used sparingly.
UV sterilizers do produce small amounts of ozone which increases oxidation of organics,dissolved oxygen,skimmer production.
What is your evidence for that production of ozone in seawater by the wavelengths used in a UV sterilizer? Remember, it is not a UV being run in air.
What is your evidence for that production of ozone in seawater by the wavelengths used in a UV sterilizer? Remember, it is not a UV being run in air.
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I am not a chemist, nor do I claim to be, the evidence I found is anecdotal but makes sense. Germicidal lamps used in UV sterilizers emit ozone. Yes, ozone production is more efficient in air but is still evident when passed through seawater. I heard this from Bob Fenner at MACNA this year. Also, while trying to collect evidence I came across a post, written by yourself, on reefs.org and an article you wrote in Reefkeeping magazine that agrees with this. There is also an article on WWM by Bob Fenner that agrees with this. I am assuming this information was correct.
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Whys
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UV is sometimes used to help control algae blooms by killing the free floating spores. UV will also kill many other micro-organisms in the water column. Many of these are beneficial and best left alive.
I consider UV a "when needed" device. I haven't needed mine yet, but have it ready.
I consider UV a "when needed" device. I haven't needed mine yet, but have it ready.
I don't recall ever writing that a UV sterilizer sending UV at 254 nm into seawater produces ozone. In fact, the reason I challenge it is that I expect it does not. If I ever wrote that, I was probably mistaken. If Bob Fenner wrote that, I expect he was mistaken too. This link has more:
http://www.coolantconsultants.com/ozone_technologies.htm
from it:
"The important distinction to make in this section is that ozone is not generated by 254 nm systems. In fact, ozone is actually destroyed by ultraviolet light at that frequency. 254 nm systems, referred to as ultraviolet sterilizers or germicidal sterilizers, inactivate organisms by affecting their ability to reproduce"
One can generate ozone with an appropriate wavelength of UV in air, but such generators use 185 nm typically, not the longer wavelengths used in a UV sterilizer. I discuss that process here, and it is discussed in the above link too:
http://reefkeeping.com/issues/2006-04/rhf/index.php#6
http://www.coolantconsultants.com/ozone_technologies.htm
from it:
"The important distinction to make in this section is that ozone is not generated by 254 nm systems. In fact, ozone is actually destroyed by ultraviolet light at that frequency. 254 nm systems, referred to as ultraviolet sterilizers or germicidal sterilizers, inactivate organisms by affecting their ability to reproduce"
One can generate ozone with an appropriate wavelength of UV in air, but such generators use 185 nm typically, not the longer wavelengths used in a UV sterilizer. I discuss that process here, and it is discussed in the above link too:
http://reefkeeping.com/issues/2006-04/rhf/index.php#6
Interesting article,good read. That article seems to be quite cut and dry, stating ozone is created at 185 nm and destroyed at 254 nm. The way I understand it is most aquarium UV lamps have a range of 185-254 nm. 254 nm is the peak wavelength for these lamps but they still emit shorter wavelengths. Wouldn't the shorter wavelengths near 185 nm, at the low end of the range produce a small amount of ozone?
If they produced 185 nm in air, yes. I am not sure that producing it in seawater makes any ozone, nor do I know whether they produce any significant amount of the shorter wavelength. They also point out that in air the 254 breaks down ozone.
I used 3 of them totaling 94 watts primarily for disease control and water clarity. Maybe, they helped against against some diseases and maybe they didn't. I removed them 2 months ago since I decided to upgrade bacteria plankton in the system. There has been no discernable ill effect to fish or water clarity. I had also read in a number of places that they produce a small amount of ozone but that was never my reason for using them and I'll take Randy's word on that issue.
OK, well, I think Bob is wrong. 
Other than his say so, does he have any evidence?
I cannot even imagine how it could possibly happen.
As I show in the article for the theory of UV formation of ozone:
During UV exposure at this wavelength, O2 molecules in air passing near the bulb absorb the light and are broken apart:
O2 ---> 2O
As with electric discharge units, these oxygen atoms can then combine with O2 to form ozone:
O + O2 ---> O3 (ozone)
For this to happen we'd need:
1. 185 nm light to be produced by the sterilizer.
2. For the O2 in the water to absorb the 185 nm UV before the hugely predominating water molecules and other chemicals in seawater do so.
3. For O atoms to be released from the excited O2 as happens in gas phase.
4. For the O to find, among the vast array of other things to react with in seawater, an O2 molecule to react with.
5. For the O and O2 to react as they do in the gas phase to make O3.
6. For the 254 nm light which is known to break ozone apart to not actually hit the O3 produced
IMO, issues 2, 4 and 6 would each individually make this incredibly unlikely, and together, IMO, they make it not going to happen.
My reading of the literature of UV and seawater suggests that other things like hydroxyl radical, which may have oxidizing properties as well, will be formed. But to say it produces ozone would not seem to be supported by any literature I could find.
Other than his say so, does he have any evidence?
I cannot even imagine how it could possibly happen.
As I show in the article for the theory of UV formation of ozone:
During UV exposure at this wavelength, O2 molecules in air passing near the bulb absorb the light and are broken apart:
O2 ---> 2O
As with electric discharge units, these oxygen atoms can then combine with O2 to form ozone:
O + O2 ---> O3 (ozone)
For this to happen we'd need:
1. 185 nm light to be produced by the sterilizer.
2. For the O2 in the water to absorb the 185 nm UV before the hugely predominating water molecules and other chemicals in seawater do so.
3. For O atoms to be released from the excited O2 as happens in gas phase.
4. For the O to find, among the vast array of other things to react with in seawater, an O2 molecule to react with.
5. For the O and O2 to react as they do in the gas phase to make O3.
6. For the 254 nm light which is known to break ozone apart to not actually hit the O3 produced
IMO, issues 2, 4 and 6 would each individually make this incredibly unlikely, and together, IMO, they make it not going to happen.
My reading of the literature of UV and seawater suggests that other things like hydroxyl radical, which may have oxidizing properties as well, will be formed. But to say it produces ozone would not seem to be supported by any literature I could find.
Maybe you should prove it wrong instead
:lol:
I didn't assert something that is not ever mentioned in the scientific literature, but I did give a link to a knowledgeable web site that specifically states what I claimed, I gave what I think are quite solid reasons why it will not happen, and I can flood the thread with more articles that show what UV does to seawater if that might convince you. If ozone is not ever produced in seawater by a UV sterilizer, you are hoping that I'll find a scientific paper that tests that hypothesis and shows it to not be true? No one would publish such an article even if someone did bother to test it.
That said, you can believe who and what you want. Big names in the reef hobby often say things that end up being wrong. This is especially true in chemistry areas. You should perhaps not be so accepting of assertions by folks, especially outside of their field of expertise, without asking exactly why they think what they do.
FWIW, inaccurate chemical assertions by all manner of folks are why I spend so much of my time trying to give correct information about coral reef chemistry. The better informed folks are, the less likely they are to be fooled into using bogus products, follow suboptimal strategies, or even give up the hobby in frustration when problems seem impossible to understand or solve.
:lol:
I didn't assert something that is not ever mentioned in the scientific literature, but I did give a link to a knowledgeable web site that specifically states what I claimed, I gave what I think are quite solid reasons why it will not happen, and I can flood the thread with more articles that show what UV does to seawater if that might convince you. If ozone is not ever produced in seawater by a UV sterilizer, you are hoping that I'll find a scientific paper that tests that hypothesis and shows it to not be true? No one would publish such an article even if someone did bother to test it.
That said, you can believe who and what you want. Big names in the reef hobby often say things that end up being wrong. This is especially true in chemistry areas. You should perhaps not be so accepting of assertions by folks, especially outside of their field of expertise, without asking exactly why they think what they do.
FWIW, inaccurate chemical assertions by all manner of folks are why I spend so much of my time trying to give correct information about coral reef chemistry. The better informed folks are, the less likely they are to be fooled into using bogus products, follow suboptimal strategies, or even give up the hobby in frustration when problems seem impossible to understand or solve.
Remarkably, I found one. 
This scientific article from last year claims that irradiation of salt water solutions with a germicidal lamp produces NO ozone:
Hydroxyl radical generation and bactericidal effects in salt solutions of low concentration after ultraviolet irradiation and magnetic treatment. Iwasawa, Atsuo; Takahashi, Noriko; Nakamura, Yoshiko; Nishimoto, Yuko. Dep. of Clinical Pthology, Showa Univ. Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama, Japan. Bokin Bobai (2008), 36(5), 285-291.
Abstract
In NaCl, MgCl2, KCl and CaCl2 solns. of less than 100 mmol/L, we measured hydroxyl radicals and the bactericidal effect on Escherichia coli after magnetic treatment by a permanent magnet and irradn. with UV rays of 254 nm. We obtained the following results: 1. Increases in hydroxyl radicals and bactericidal effects on E.coli were confirmed after magnetic treatment of salt solns. of low concn. Greater amts. of hydroxyl radicals led to higher redns. of E.coli. 2. The increase in hydroxyl radicals was not confirmed after irradn. with UV rays of 254 nm to the salt solns. It was considered that the dissolved oxygen in the soln. did not generate ozone, a precursor of the hydroxyl radical. 3. Bactericidal effects on E.coli by irradn. with UV rays were confirmed, and it was considered that the UV rays had directly affected the bacteria. From an environmental viewpoint, it is important to reduce chlorine including chloride ions in brackish water and inhibit the diffusion of chlorine gas into the atm. If bactericidal effects could be confirmed in the samples without the use of available chlorine, such a treatment may be applicable to the environment. In this study, we confirmed the redn. of E.coli by magnetic treatment in salt solns. near 10 mmol/L in salt concn. The redn. rate of bacteria was assocd. with the generated amt. of hydroxyl radicals with strong oxidn. This result suggests the possibility of environmental applications.
This scientific article from last year claims that irradiation of salt water solutions with a germicidal lamp produces NO ozone:
Hydroxyl radical generation and bactericidal effects in salt solutions of low concentration after ultraviolet irradiation and magnetic treatment. Iwasawa, Atsuo; Takahashi, Noriko; Nakamura, Yoshiko; Nishimoto, Yuko. Dep. of Clinical Pthology, Showa Univ. Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama, Japan. Bokin Bobai (2008), 36(5), 285-291.
Abstract
In NaCl, MgCl2, KCl and CaCl2 solns. of less than 100 mmol/L, we measured hydroxyl radicals and the bactericidal effect on Escherichia coli after magnetic treatment by a permanent magnet and irradn. with UV rays of 254 nm. We obtained the following results: 1. Increases in hydroxyl radicals and bactericidal effects on E.coli were confirmed after magnetic treatment of salt solns. of low concn. Greater amts. of hydroxyl radicals led to higher redns. of E.coli. 2. The increase in hydroxyl radicals was not confirmed after irradn. with UV rays of 254 nm to the salt solns. It was considered that the dissolved oxygen in the soln. did not generate ozone, a precursor of the hydroxyl radical. 3. Bactericidal effects on E.coli by irradn. with UV rays were confirmed, and it was considered that the UV rays had directly affected the bacteria. From an environmental viewpoint, it is important to reduce chlorine including chloride ions in brackish water and inhibit the diffusion of chlorine gas into the atm. If bactericidal effects could be confirmed in the samples without the use of available chlorine, such a treatment may be applicable to the environment. In this study, we confirmed the redn. of E.coli by magnetic treatment in salt solns. near 10 mmol/L in salt concn. The redn. rate of bacteria was assocd. with the generated amt. of hydroxyl radicals with strong oxidn. This result suggests the possibility of environmental applications.
