Properly sizing UV Sterilizers

[johnr2604]

ichthyoid;463978 wrote: Chris, I have a couple of concerns with the data presented on Aqua UV's sizing chart:

1) I did not see a reference to their recommended dosages,

2) I did find a reference to a recommended dosage for human drinking water, issued by the US Public Health Service of 16,000 microwatt*seconds/square centimeter, (also apparently adopted as a world standard).
http://enaqua.com/enweb/index.php?option=com_content&view=article&id=15&Itemid=11">http://enaqua.com/enweb/index.php?option=com_content&view=article&id=15&Itemid=11</a>
(see bottom of page)

3) I find it interesting that our drinking water can be protected by a UV dosage 21 times lower than that required to keep a fish from getting sick.

3) The chart that you kindly provided (I assume copied and pasted) shows the UV required for many different organisms to be [B]99.999%[/B] effective for a [B]single pass[/B] through the sterilizer (technically this should be 99.9995+/-%, or log 10^6, but I won't pick their statistics apart).

4) The above kill efficacy exceeds almost any medical/pharmacological treatment efficacy rate that I am aware of. If our medicines were required to meet this degree of efficacy, antibiotics would have never made it to market! (check with your boss/Mrs.-lol)

5) If I remember statistics correctly, the number posted by Aqua UV would indicate:
-a dosage of 1/4 that (84,000microW*s/cm^2), would yield a [B]95+% kill[/B]
[B]-[/B]a dosage of 1/16 that (21,000microW*s/cm^2), would yield a [B]69+% kill[/B]
(this lower dose in good agreement with the US Public Health dose above)

Based on this, I believe that it is invalid to say that a lower powered unit is ineffective, but very valid to say that it will require multiple passes for the [B]same degree[/B] of efficacy. Being that, in general, our tanks are closed systems, the application of lower powered UV is valid with certain caveats (ie-keep the bulbs changed regularly, and keep the flow through them reasonable).

Also-

6) This subject gave me reason to research a little deeper, and I found at least one reference to a theory that UV simply boosts the RedOx potential of water thus enhancing the fishes resistance and/or weakening the pathogens. This theory would seem to lend credence to the statements by IAMRIT and others, that good water quality is key. I can also attest that this [B]is[/B] important from my early days in the hobby, when water quality was not always viewed to be as important as it is now, and we had fewer/less effective methods to address such. Disease was [B]much[/B] more of an issue.
[IMG]http://www.americanaquariumproducts.com/Aquarium_Ich.html">http://www.americanaquariumproducts.com/Aquarium_Ich.html</a>
(second paragraph from the bottom

I have used the same Aquanetics UV sterilizers for well over 20 years with good results. I feel confident that there are others that can attest to good efficacy, with otherwise 'underpowered' units. I have no doubt that the choice of higher intensity UV is a great solution, and gives much peace of mind. Higher powered units may be used at much higher flow rates, which is a definite plus as well. These units also provide a much greater 'margin of safety' with regard to the inevitable decrease in output over time.

I hope that what I have shown here has been of some benefit. I also hope that those possessing smaller/lower powered units do not abandon them, but realize their utility, albeit in a more limited context. If I have overlooked anything and/or made mistakes, I apologize in advance, as I am typing this 'on the fly' and without review. Thanks-[/QUOTE]Thank you for your input. Being one of those people that runs what some might consider an undersized unit for my system. I simply have seen a benefit from running it and would never ditch it. While I don't know how effective it would be cleaning a full blown ich outbreak, I can say I believe it Is a help in preventing it. Plus there are other benefits such as not cleaning glass as often and even better water clarity which were the firsts things I noticed when I installed the unit last year.

 

[mojo]

ichthyoid;463978 wrote: Chris, I have a couple of concerns with the data presented on Aqua UV's sizing chart:

1) I did not see a reference to their recommended dosages,

I wouldn't put any weight into it, even if they did. The recommended dosages came from a 3rd party, not from someone trying to sell a product.

2) I did find a reference to a recommended dosage for human drinking water, issued by the US Public Health Service of 16,000 microwatt*seconds/square centimeter, (also apparently adopted as a world standard).
http://enaqua.com/enweb/index.php?option=com_content&view=article&id=15&Itemid=11">http://enaqua.com/enweb/index.php?option=com_content&view=article&id=15&Itemid=11</a>
(see bottom of page)

3) I find it interesting that our drinking water can be protected by a UV dosage 21 times lower than that required to keep a fish from getting sick.[/QUOTE]Interesting, maybe, but I fail to see the importance. Humans are not marine animals. You're comparing apples and oranges. I'm guessing that if you looked up the toxicity levels of iodine and other elements, they'd be different for marine animals and humans, too; the two simply can't be compared.

For that matter, humans can probably be killed with enough UV radiation as well, but it'd be far, far higher than is required for Ich. But it doesn't mean we should use that number, either...

[QUOTE=]

Based on this, I believe that it is invalid to say that a lower powered unit is ineffective, but very valid to say that it will require multiple passes for the [B]same degree[/B] of efficacy. Being that, in general, our tanks are closed systems, the application of lower powered UV is valid with certain caveats (ie-keep the bulbs changed regularly, and keep the flow through them reasonable).[/QUOTE]Can you show research that supports this extrapolation with Crypocaryon?

UV works by denaturing the proteins in the organism's DNA. This can only happen if the UV is powerful enough to actually reach the DNA within the cells. I can only presume that some organisms have more or less protection from this radiation, and thus it takes more or less UV to penetrate and be effective. How much so? I don't know- that's why I rely on the research already done.

Based on the fact that you need a certain power level to penetrate the cell membranes, you can't just extrapolate downward arbitrarily and say that a lower-powered unit is just as effective if multiple passes are used, at least not without research. Multiple passes imply that the damage is additive, and I haven't seen any research one way or another.


[QUOTE=]6) This subject gave me reason to research a little deeper, and I found at least one reference to a theory that UV simply boosts the RedOx potential of water thus enhancing the fishes resistance and/or weakening the pathogens.[/QUOTE]I'm not rejecting this particular claim, but I've run ozone for years, and it wasn't until I added a large UV sterilizer that I ended my Ich problems. Ozone directly increases the redox of a system, so presumably it'd have the same effect.

[QUOTE=]I have no doubt that the choice of higher intensity UV is a great solution, and gives much peace of mind. Higher powered units may be used at much higher flow rates, which is a definite plus as well. These units also provide a much greater 'margin of safety' with regard to the inevitable decrease in output over time.[/QUOTE]My post wasn't necessarily to find the most efficient unit that would be effective for a tank, but rather to inform others that a minimum size is required - a 9w sterilizer won't work on my 800g system. If it's oversized, then so be it, but at least we know it's effectiveness. Anything less is simply unknown without more research.

[QUOTE=]I hope that what I have shown here has been of some benefit. I also hope that those possessing smaller/lower powered units do not abandon them, but realize their utility, albeit in a more limited context. [/QUOTE]I disagree. The only thing worse than having some equipment that you know is underpowered is having equipment that you think is sufficient.

Don't get me wrong - I'm glad that someone is challenging my post, but I simply don't see where you can extrapolate downward and feel comfortable without hard evidence to support it.


With your permission, I'd like to move this tangential discussion to the end of the UV post, to keep this thread on track...

 

[ichthyoid]

mojo;463990 wrote: I wouldn't put any weight into it, even if they did. The recommended dosages came from a 3rd party, not from someone trying to sell a product.

Agreed, my point was to illuminate lack of objectivity.

Interesting, maybe, but I fail to see the importance. Humans are not marine animals. You're comparing apples and oranges. I'm guessing that if you looked up the toxicity levels of iodine and other elements, they'd be different for marine animals and humans, too; the two simply can't be compared.

My point is not to compare apples to oranges</em>, but to illustrate that our Federal Government feels much lower levels are adequate to protect humans. I do not believe that US Public Health would stand for significant levels of 'critters' in our drinking water. Perhaps there are 'other' mitigating factors at work (multiple stages of water treatment, presence of chlorine, etc,)

For that matter, humans can probably be killed with enough UV radiation as well, but it'd be far, far higher than is required for Ich. But it doesn't mean we should use that number, either...

Can you show research that supports this extrapolation with Crypocaryon?

I did. They cited statistical kill ratio's and I extrapolated back from that number based on standard deviation (6 sigma, vs 4 sigma, vs 2 sigma). If their math is correct, then I feel comfortable with mine; but would like to see their base data first.

UV works by denaturing the proteins in the organism's DNA. This can only happen if the UV is powerful enough to actually reach the DNA within the cells. I can only presume that some organisms have more or less protection from this radiation, and thus it takes more or less UV to penetrate and be effective. How much so? I don't know- that's why I rely on the research already done.

UV denaturation is a statistical event, it's not all-or-nothing, there is a normal distribution. Also, I am somewhat knowledgable of UV photochemistry (designed photodegradeable fabrics/cigarette filters, etc and helped develop the tests for these. Also determined that they are ruled by second order kinetics, ie-there is an exposure AND temperature dependence).

Based on the fact that you need a certain power level to penetrate the cell membranes, you can't just extrapolate downward arbitrarily and say that a lower-powered unit is just as effective if multiple passes are used, at least not without research. Multiple passes imply that the damage is additive, and I haven't seen any research one way or another.

The formula says otherwise, it is microwatts x seconds/cm^2. The seconds term indicates that this IS a time dependent mechanism.
(longer=stronger)

The bulbs in a UV sterilizer emit primarily 254 nanometer radiation, which is of fixed energy. More watts does not make a photon penetrate any more deeply, but more photons increase the likelyhood that the event will occur. More sun gives sunburn in less time vs less sun does so in longer time. Both=same result (per your prior example).

I'm not rejecting this particular claim, but I've run ozone for years, and it wasn't until I added a large UV sterilizer that I ended my Ich problems. Ozone directly increases the redox of a system, so presumably it'd have the same effect.

As stated, it is a theory, not a claim.</em>
BTW-did your ozone increase ORP significantly, and if so, how much? Just curious- thx.

My post wasn't necessarily to find the most efficient unit that would be effective for a tank, but rather to inform others that a minimum size is required - a 9w sterilizer won't work on my 800g system. If it's oversized, then so be it, but at least we know it's effectiveness. Anything less is simply unknown without more research.

Exactly, and as I see it, unsupported by the manufacturer. What is the saying?- "there are lies, d***ed lies and statistics" (Mark Twain-I believe)

I disagree. The only thing worse than having some equipment that you know is underpowered is having equipment that you think is sufficient.

Hmm, perhaps, but a lot of the later supported this hobby for years!

Don't get me wrong - I'm glad that someone is challenging my post, but I simply don't see where you can extrapolate downward and feel comfortable without hard evidence to support it.

See above. Just my $0.02. I'm not attacking here, just interested in the topic and the facts.


With your permission, I'd like to move this tangential discussion to the end of the UV post, to keep this thread on track...

Agreed

 

[ichthyoid]

After thinking about this, I believe that I understand why the manufacturer used the irradiance numbers that they do. The drinking water purification systems manufacturers must ASSUME a single pass through the UV sterilizer. After treatment the water goes on to be consumed. (One shot is ALL they get to kill the 'bugs')

That is NOT the case in an aquarium, which is almost always a closed system. (closed loop)

Since the treatment is time dependent, and therefore cumulative, what really</em> matters is that the statistical kill time for all organisms in the system be less than the reproduction cycle of that organism.

This was illustrated years ago in 'the Chinese Army' paradox. It goes something like this:

There are so many men in China that if they marched 8 abreast and you mowed them down with a machine gun, one row every second, you would never reach the end. The population's ability to reproduce would exceed the hypothetical kill rate.

 

[ichthyoid]

I also found a reference via Wikipedia that states...

"It has been found that http://en.wikipedia.org/wiki/Protists"><span style="color: #002bb8">protists</span></a> are able to survive high UV-C doses but are sterilized at low doses."

[IMG]http://en.wikipedia.org/wiki/Ultraviolet#Sterilization">http://en.wikipedia.org/wiki/Ultraviolet#Sterilization</a>
(see 'Disinfecting drinking water' section)

So it would appear that 'killing efficacy' and 'sterilization efficacy' require two completely different irradiance levels for parasitic protozoans, but that they both would likely end with the same result long term, ie-the elimination of the population. This makes sense, no?

 

[ichthyoid]

I found the NSF/ANSI standard (National Science Foundation/American National Standards Institute), which lists requirements for UV treatment of public drinking water. Below is a summary,followed by references.

NSF/ANSI Standard 55: Ultraviolet Microbiological Water Treatment Systems
Overview: This standard establishes requirements for point-of-use (POU) and point-of-entry (POE) non-public water supply (non-PWS) ultraviolet systems and includes two optional classifications. Class A systems (40,000 uwsec/cm2) are designed to disinfect and/or remove microorganisms from contaminated water, including bacteria and viruses, to a safe level. Class B systems (16,000 uw-sec/cm2) are designed for supplemental bactericidal treatment of public drinking water or other drinking water, which has been deemed acceptable by a local health agency.

http://www.nsf.org/business/drinking_water_treatment/standards.asp">http://www.nsf.org/business/drinking_water_treatment/standards.asp</a>

-and a good explaination of the standard:

[IMG]http://www.wcponline.com/column.cfm?T=W&ID=1555&AT=W">http://www.wcponline.com/column.cfm?T=W&ID=1555&AT=W</a>

Here is a certification from a manufacturer listing log 4 reduction (99.99%) of pathogens, including Giardia and Cryptosporidium at 40mJ/cm^2.

[IMG]http://74.125.47.132/search?q=cache:q4_f4Gg39BkJ:www.bipurewater.ca/uploads/doc/technical/Sterilight%2520NSF.doc+ANSI/NSF+Standard+55&cd=7&hl=en&ct=clnk&gl=us">http://74.125.47.132/search?q=cache:q4_f4Gg39BkJ:www.bipurewater.ca/uploads/doc/technical/Sterilight%2520NSF.doc+ANSI/NSF+Standard+55&cd=7&hl=en&ct=clnk&gl=us</a>

Note of interest- is that the units have been changed to mJ/cm^2 to comply with international standards (SI). The actual number stays the same (mW*sec=mJ).

I believe that if I can drink it, then my fish should probably be ok too.

 

[mojo]

ichthyoid;465410 wrote: I believe that if I can drink it, then my fish should probably be ok too.

Interesting conclusion, since the biology of humans and marine animals is very different...

As an interesting aside for those who eat sushi - you'll never find raw freshwater fish (or eel), even at a sushi restaurant. Turns out that our bodies don't have any problem with anything that might be in marine fish (assuming some level of preparation), but not so with freshwater fish. Different biologies. This really isn't germane to the UV debate, but something to think about when making assumptions for your reef tank based on data for your drinking water.

 

[ichthyoid]

mojo;465430 wrote: Interesting conclusion, since the biology of humans and marine animals is very different...

I won't debate the bioloigal differences (or similarities), I was specifically referring to the 99.99% reduction at 40mJ/cm^2 of UV.

As an interesting aside for those who eat sushi - you'll never find raw freshwater fish (or eel), even at a sushi restaurant. Turns out that our bodies don't have any problem with anything that might be in marine fish (assuming some level of preparation), but not so with freshwater fish. Different biologies. This really isn't germane to the UV debate, but something to think about when making assumptions for your reef tank based on data for your drinking water.

I do not concur with this statement.

I am a consumer of sushi, but also very aware of the risks. It is well documented that salmonella, vibrio, cholera, foreign strains of E. Coli, mycobacterium, as well as worms, other parasites and even ciguatera toxins may be ingested from fish/seafood; sometimes raw, undercooked and in the case of ciguatoxin it does not matter. Ciguatoxin poisoning is potentially lethal. I have contracted food borne illness myself from what was likely a vibrio infection from 'fresh' raw oysters. 24 hours of total misery! Dinoflagellates are another source of illness ('red tides'), with the ones on the Pacific coast being potentially lethal as well. Several years ago a professional baseball player contracted a marine parasite from sushi in and it took a year to cure!

Salmonella ref.

http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-pubs-2004-cdi2804-pdf-cnt.htm/$FILE/cdi2804p.pdf">http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-pubs-2004-cdi2804-pdf-cnt.htm/$FILE/cdi2804p.pdf</a>

Vibrio ref.

[IMG]http://infectiousdiseases.about.com/od/g/a/Sushi.htm">http://infectiousdiseases.about.com/od/g/a/Sushi.htm</a>

Mycobacterium from handling sushi,

[IMG]http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763814/">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763814/</a>

Ciguatera ref.

[IMG]http://en.wikipedia.org/wiki/Ciguatera">http://en.wikipedia.org/wiki/Ciguatera</a>

Parasite ref.

[IMG]http://content.nejm.org/cgi/content/brief/320/17/1124">http://content.nejm.org/cgi/content/brief/320/17/1124</a>

General sushi risk, etc.

[IMG]http://www.articlesbase.com/health-articles/sushi-health-risks-risks-of-sushi-such-as-parasites-heavy-metals-bacteria-1132521.html">http://www.articlesbase.com/health-articles/sushi-health-risks-risks-of-sushi-such-as-parasites-heavy-metals-bacteria-1132521.html</a>

 

[mojo]

I do not concur with this statement.

Not surprising.

Seafood that lives in salt water has a very small risk of parasitic invasion. The human body will kill most of them during digestion. People that are immune deficient, young or older, pregnant or taking antibiotics do have a higher risk of acquiring parasites from seafood that has not been previously frozen. Seafood that lives in fresh water or travels from fresh water to salt water will have a significantly higher risk of parasites if the product is eaten “fresh”. (http://www.kaifoodshow.com/index/chew-on-this/54-sushi-grade-is-freshright-.html">source</a>)[/QUOTE]
[QUOTE=]Another issue that comes up occasionally is the use of fresh-water fish for making sushi. I offer a resounding "NO." Fresh-water fish can contain bacteria and parasites that are more prolific or possibly dangerous than salt-water fish. Species such as salmon that spend a large portion of their lives in the ocean are generally considered safe, as well as its permanent denizens, but it is recommended that people not eat fresh-water fish raw due to the increased potential for health risks, some of which can be extremely dangerous. ([IMG]http://www.sushifaq.com/ffaq.htm#Fresh%20Water%20Fish">source</a>)[/QUOTE]
[QUOTE=]And before you ask, tapeworms require a freshwater stage in their lifecycle, so as long as you stick to the saltwater fish you should be fine. No one should ever eat freshwater fish raw under any circumstances as the risks of parasitic infection increase dramatically due to the large number of freshwater parasites that exist, the freshwater ecosystem being a much better environment for parasitic creatures. ([IMG]http://www.sushifaq.com/sushi-health-risks.htm">source</a>)[/QUOTE]

I'm unsubscribing from this thread. It's going off topic and this debate seems pointless.

 

[mojo]

IamRit;465544 wrote: Can I hook up 2 - 120W UV and have the same effectiveness as a single 240W unit?

Yes, especially since almost all 240w sterilizers are simply two 120w units stuck together.

 

[simon_kruger]

Rit, Chris, Im so excited I'm getting my 320w UV this week. I'll have it plumbed by the weekend.

320w at 1000gallons an hour.

 

[oz]

mojo;465485 wrote: I'm unsubscribing from this thread. It's going off topic and this debate seems pointless.

I would really like to see this thread focus on its intention - FISH and nothing else. What is good for humans, dogs, birds, whatever can be addressed in another thread.

Can the mods move all the non-fish related posts to another thread?

I've learned a lot either way by reading and posting in this thread. I wanted to post some actual results with the 240W unit I am putting on my system shortly.

 

[johnr2604]

Oz;465679 wrote: I would really like to see this thread focus on its intention - FISH and nothing else. What is good for humans, dogs, birds, whatever can be addressed in another thread.

Can the mods move all the non-fish related posts to another thread?

I've learned a lot either way by reading and posting in this thread. I wanted to post some actual results with the 240W unit I am putting on my system shortly.

I personally see a benefit in discussing whats good for humans in this thread. After all this is probably where most research on UV's has taken place. Plus the standards for humans tend to have a pretty good safety factor figured in. Far more than other animals.

 

[tony_caliente]

This is a well-timed thread, ar least for me. I am contemplating a UV for my 55g. I was thinking about supplying water to it using a small canister filter that I will probably just put some floss or bio-mech in. What do you think? What UV brands do you like?
Can you think UV and canister filter combo that you? Thank you.
PS. I don't have to have the most sophisticated, expensive or best. I just want something that works and is easy to maintain (if that leads to the the most sophisticated, expensive and best, so be it). Gracias!

 

[mojo]

Tony_Caliente;466771 wrote: This is a well-timed thread, ar least for me. I am contemplating a UV for my 55g. I was thinking about supplying water to it using a small canister filter that I will probably just put some floss or bio-mech in. What do you think? What UV brands do you like?
Can you think UV and canister filter combo that you? Thank you.
PS. I don't have to have the most sophisticated, expensive or best. I just want something that works and is easy to maintain (if that leads to the the most sophisticated, expensive and best, so be it). Gracias!

I can recommend AquaUV, but, as I said above, only because I have experience with them. They are neither the best nor the worst.

I'd recommend not using the canister filter - the filter floss or mechanical filtration will get clogged over time and become a nitrate filter. Just use a powerhead.

 

[skriz]

I'd reccomend Emperor. IMO, they're not only the best, but also the best bang for your buck.

 

[skriz]

The 57w Aqua UV is notoriously bad. They blow ballasts like it's nobody's business. We have a box of them collecting dust. Make sure you check it often to verify that it's on.

 

[grouper therapy]

Aquaticco;470615 wrote: I run the 57 watt on my 210. Just hooked it up though so I can't give you an honest opinion. I did go with the wiper as well

Doug

I have run two of the 57 watt aqua uv flawlessly for two years. I'm not sure of the other brands never had to buy one since both of mine were purchased used 3 years ago and I only replaced the bulbs. I guess they work pretty good ,I have 10 tangs in my tank and never had ich issues.

 

[lilrobb]

mojo;465563 wrote: Yes, especially since almost all 240w sterilizers are simply two 120w units stuck together.

I actually have a problem with this statement.
While it was explained earlier that it is all about the POWER of the unit and how deep the UV radiation penetrates the cell - how does this compare to hooking up two 120W ones in-line?
it doesn't fortify the raditation, just prolongs dwell time...

Robb

 

[grouper therapy]

LilRobb;475451 wrote: I actually have a problem with this statement.
While it was explained earlier that it is all about the POWER of the unit and how deep the UV radiation penetrates the cell - how does this compare to hooking up two 120W ones in-line?
it doesn't fortify the raditation, just prolongs dwell time...

Robb

+1 if I slow the water through my 57 watt down half of it's recommended flow rate then am I accomplishing the same as a n 114 watt uv and just processing less water per hour? I would think the a single higher wattage uv(400 watt viper) would penetrate the cells better than prolonged exposure would. Any thoughts?