UV Sterilization

[mcarroll]

3 hours ago, Humblefish said:

Here's a monkey wrench:
 

Source: https://edis.ifas.ufl.edu/fa164

 

Now find my a hobbyist grade UV that has a UV dose anywhere near 280,000 µWsec/cm2?? 😕

There is no gotcha...those are usage guidelines.

 

Now here's the whole quote:

Quote

Use of ultraviolet (UV) sterilization to kill theronts has been suggested, based on research involving Ichthyophthirius multifiliis (freshwater "ich"). The recommended UV dose for Ichthyophthirius theronts is 100,000 µWsec/cm² (Hoffman 1974). However, UV doses required for Cryptocaryon irritans are anecdotal or extrapolated, and range from 280,000 µWsec/cm² (industry numbers) to 800,000 µWsec/cm² (Colorni and Burgess 1997).

 

Theronts must go through the UV sterilization unit in order to be exposed, so any theronts that are not exposed to UV radiation and remain in the tank or holding areas will be unaffected. Similarly, encysted tomonts within the tank or holding area will not be affected

Again just so it's clear, they are NOT saying that UV won't work.   They are saying that's how to make it work...or guidelines to start with.  But that was in 1974 and 1997 (which is paraphrasing Spotte, I think...uncredited?  Or at least I've read the same number being attributed to Spotte.)...and was purely an extrapolated estimate based on their size.

 

The thing is, folks have been deploying and using UV for 50-some years now in real life....20-some years with specific knowledge on these fish diseases.

 

I actually already explained the "how" earlier, but a recap. is a totally fair ask.

 

You modulate the UV exposure by either varying the watts of the UV bulb, or varying the flow.  (Or both.)  That's just how you do it with UV.   More flow gives your a reduced exposure-per-pass whereas less flow gives you an increased exposure.

 

I can tell you that a 280,000 watt UV system is not required, if that's what the IFAS article seems to suggest.  

 

"UV power" is not what the exposure units are expressing.  Power (micro-Watts) is just an aspect of exposure.  (280,000µW is only .28 Watts anyway, even if power was what "µWsec/cm2" was expressing.  

 

I'm not sure it's necessary to using UV successfully (something like the sizing guide at the end is usually all you need), but if you really want nitty gritty, try UV FAQs at the International UV Association:

Quote

Question 6: Many of the specifications I have read concerning UV dosage ratings are in microwatt seconds/cm2. For example, one such unit is rated at 16,000 microwatt seconds/cm². I notice a UV dosage in your calculations or 87 mW/cm2. How do you convert this number to microwatt seconds/cm²?

Many of the specifications I have read concerning UV dosage ratings are in microwatt seconds/cm2. For example, one such unit is rated at 16,000 microwatt seconds/cm². I notice a UV dosage in your calculations or 87 mW/cm2. How do you convert this number to microwatt seconds/cm²?

Most scientists and engineers in the UV business now use the units "mJ/cm²" (millijoule per square centimeter) or "J/m²" (joule per square meter) for UV dose (the correct term is "fluence"). The units "J/m²" are used in most parts of the world except for North America, where "mJ/cm²" are used (1 mJ/cm² = 10 J/m². The old term "mW-s/cm²" (milliwatt-second per square centimeter) is equivalent to "mJ/cm²", since a "W-s" is the same as a "J" (joule). Note that 1000 microwatt = 1 milliwatt.

 

Note that the term "dose" ("dosage" is a word that is redundant with "dose" and should be discouraged) is normally applied in situations where the radiation is totally absorbed (e.g., UV in sunlight absorbed by the skin to cause sun tanning or sun burning). Since less than 1% of the UV incident on a microorganism is absorbed, the term "dose" is not appropriate for this situation. This is why the term "fluence" (which is defined in terms of UV "incident" on a tiny sphere from all directions) is more appropriate.

The units "mW/cm²" (for fluence rate or irradiance) are often confused (as you have in your question) with the units "mJ/cm2" (for fluence or UV dose). The "fluence" (UV dose) is obtained by multiplying the "fluence rate" (or irradiance) (units "mW/cm²") by the exposure time in seconds.

 

Or this explanation from a water purification industry magazine (Water Conditioning & Purefecation Magazine):

Quote

Ultraviolet (UV) light is known to be an effective disinfectant of most microorganisms by damaging an organism’s DNA thus preventing the organism from multiplying, and making it incapable of causing infection in a host. Due to varying absorbance characteristics of different organisms and abilities of organisms to repair their DNA following exposure to UV, the amount (dose) of UVrequired to cause irreversible damage varies among species.

 

UV dose is expressed as millijoules per square centimeter (mJ/cm2), which is equal to milliWatt-seconds per square centimeter (mWsec/cm2) or 1,000 microWatt-seconds per square centimeter (µWsec/cm2). For example, to achieve 4 log (99.99 percent) inactivation of vegetative bacteria, such as Escherichia coli, 5-to-10 mJ/cm2 are necessary. To achieve the same level of inactivation of spore forming bacteria and viruses, 25-to-50 mJ/cm2 are needed. Recent studies have shown that protozoa (Giardia and Cryptosporidium) are quite sensitive to UV, so that 2-to-10 mJ/cm2 would provide at least 4 log inactivation.1,2

 

James Bolton and Larry Henke provided an excellent review of UV disinfection in a 1999 WC&P article.3 It’s useful to reiterate two of their points. First, UV is a physical process. Photons of germicidal UV (those roughly in the 260-to-265 nanometer [nm] range) impact the DNA of target microorganisms. The result, or photoproduct, of this particular interaction is existing bonds within the DNA are broken and new ones (thymine dimers) are formed. As the DNA strands are now altered, they’re incapable of proceeding through steps necessary for replication, and thereby the organism is no longer infectious. Second, UV dose is defined as the amount of UV light, or irradiance, reaching an object multiplied by the exposure time, in seconds. In UV reactors, the primary factors that influence UV dose are the output of the UV lamp(s), the spatial relationship of the lamp(s) to the chamber, retention time, and water quality (especially parameters contributing to UV absorbance). Particulate matter and/or turbidity can reduce UV performance so effective pretreatment may be required in some instances.

 

It also might be helpful to look at AquaUV's sizing chart to see how flow rates and power levels play into the recommendations:

https://aquaultraviolet.com/wp-content/uploads/2019/06/UV-Charts-Salt-and-Fresh-Water-Web.pdf

 

The ratings for targeting parasites on most UV units is adequate in my experience on the commercial level as well as the hobby level....that usually amounts to something like 100,000µws/cm2, but not all makers give a rating like that on their literature.  Use whatever rating the maker gives you....even the "lowly" Green Killing Machine is size-rated.

 

6 hours ago, Tamberav said:

I don't see any proof...just a link the people who make it. The flow doesn't look controllable.

 

When I go to purchase one on a vender it says recommended for green water only and they don't recommend running the unit 24/7.

 

???

 

I would just look for a used unit of one of the larger brands if the goal is parasite control. 

I'm not trying to convince you personally of anything here other than the information that I'm pointing to (a website and a thread) exists.  You just have to look at it and evaluate it for yourself.  🙂   Getting a larger unit is fine if it's appropriate for your situation.

 

For your question about a retailer's info about usage, you'll either have to quote them or link the page you're talking about so I can comment directly, or ask the site about it yourself.  It sounds like some context is missing from what you posted, but that's a guess.

 

I linked to the maker's page earlier, which I'd suggest reading if you're interested and you think those GKM units are the right fit.  Start with their page.

 

All I was trying to point out is that GKM's published ratings (each unit has a gallon range, as I pointed out earlier) seem to match real life trial and error from my dino thread where hundreds of people (at least) have repeatedly proven them to actually work.  

 

Folks haven't had to do anything too fancy in most cases to get them to work....mostly just picking the correct size, which means the largest rated size for your tank (instead being cheap and getting the smallest) and installing it into the display.  

 

The most common "incorrect tendency" wasn't to use a unit that was too small, it was to try installing it permanently or otherwise installing it into the sump....they should be installed directly to the display for the best results.  Remember it should be temporary.

 

The smaller, self-contained units (Pump+UV) like the Green Killing Machine do seem to be easier to deploy than the larger ones...no plumbing involved, pump is pre-selected, so that makes some sense.  That might make them a little more foolproof even if they are somewhat less flexible.  Larger units are obviously called for on larger systems...or multiple units if you wanted to play it that way.....eg. us one 24w unit for a 50 Gallon; use two (or more) 24w GKM's for a 100 Gallon display.

 

4 hours ago, second_decimal said:

i figured the UV would just help tip the scales a little in the direction of the fishes favor if i just drop them in.

That is exactly its function.

 

Deployed correctly, especially along with micron filtration, it can actually do quite a bit of scale-tipping.  😉

 

In many cases just a "little tip" is all your fishes need anyway....and then their immune system kicks back in.

 

4 hours ago, Tamberav said:

While experimental, my fav method right now is h2o2 baths but that is for velvet/brook, not so much ich.

It's experimental in our context, but it's a treatment that's been "on the books" so to speak for quite a while.  I'm glad you're using it and posting about it so more folks will know.  👍 The basic freshwater dip is still largely overlooked and as effective as h2o2 dips for certain things.  (Lots of these "lesser" solutions have been kind of "traditionally overlooked".)

 

If you haven't seen it (or maybe others haven't) here's a good general guide on h2o2 including dosing instructions: (e.g. 5mL of 35% peroxide would be a 10 mg/L dose in a 50 Gallon tank):

FA157/FA157: Use of Hydrogen Peroxide in Finfish Aquaculture

 

A small caveat is if anyone were considering peroxide and nothing else to cure a full-on outbreak.  Then they may be asking for more than it can deliver.  (Tho see below, as this has actually been studied.)

 

In a more typical use-case like yours – treating a few new fish "just in case" for a home tank; no outbreak – it can be a very effective tool even against Ich (really Cryptocaryon) as well as the other pests you mentioned.  It's very complimentary with UV and micron filtration too if you wanted to use all three...virtually no stress to the fish. If any it's from the 10 mg/L of h2o2...but that should be mild.

 

At least one study has looked at peroxide vs Crypto (ich) and found that even as low as 10mg/L will clear over 80% of theronts and is arguably even reef safe.

 

Check out "In vitro treatments for the theront stage of the ciliate protozoan Cryptocaryon irritans" from 2011.

https://www.int-res.com/articles/dao2011/94/d094p167.pdf

From Diseases of Aquatic Organisms Vol. 94.  

doi: 10.3354/dao02315

 

They got over 90% clearance at 50 mg/L, which I'm guessing may be on the high-side for some tanks or some fish.

 

80 isn't 100%, but you don't just ignore a tool that can be found at the grocery store (or in the USA, a health food store), used simply, at a relatively low dose, AND be 80%+ effective. 

 

Levels of H2O2 start becoming problematic for the fish beyond 80/90% effectiveness.  So, if you need more protection than peroxide (you might not) then it is simply time to send in UV and/or micron filtration – or both – to mop up that last 20%.  👍

 

(Worth pointing out that h2o2 degrades FAST in a biologically active environment like a reef tank....possible in as little as an hour or less from what I've read.)

 

Virtually all of this is covered in the book "FISH DISEASE: Diagnosis and Treatment" by Ed Noga at NC State.  At $100-$150, it's definitely an expensive book, but I think it's one that almost everyone who keeps fish could benefit from having vs being constrained by the info available within the hobby.  

 

Check out the Table of Contents.

 

Here's a great quote from the section on Health Management that kinda goes against the grain of our conventional wisdom of pre-medicating everything in QT...everything about the usage of meds should be tailored to the specific circumstance....not be applied rotely:

 

From Noga(2011), Chapter 6, p 70:

Quote

Prophylactic treatments (e.g., salt, formalin, etc.) are often advocated prior to the introduction of fish into a new environment. However, the efficacy of this procedure depends upon the specific circumstances. For example, if a fish population has a significant number of ectoparasites, it is justified to treat with an appropriate parasiticide prior to introduction in order to reduce the parasite load on the stressed fish. This is especially true for wild-caught fish, which often carry significant parasite burdens. On the contrary, if a population is clinically healthy and has no significant pathogen burden, the added stress of a drug treatment might not be advisable and might increase the susceptibility to opportunistic pathogens that are commonly resident in the environment. Thus, the proper prophylactic procedures must be tailored to each particular situation.

👏

There is a very, very good section on Quarantine as well.  

 

In fact, this book is not perfect and there are lots of things "missing" that I'd like to see in there, but IMO it covers most things really, really well.  

 

Mostly it's limited by the available research or occasionally by its focus on aquaculture-in-general vs just on our particular needs.  (Noga has a book dedicated to ornamental fish health, but I haven't seen it yet....it's cheaper so I presume it's a subset of this book....I could be wrong.)

 

 

 

 

[Tamberav]

I have a 10 watt cheapo UV and a 25 watt Aqua UV so I am familiar with them.

 

I put the 25 watt on a 22g to clear Ostreopsis dino and that crap was dead in HOURS.

 

I put the 10 watt on a 25g and it took days to even see even a tiny change. Yes, It eventually cleared it but we are measuring weeks now and not hours. Both tanks had the same issue...same strain I am sure from sharing water/frags and so on.

 

but Ostreopsis is not the same as Amyloodinium. I know velvet can overwhelm a fish fast. If I had been trying to treat velvet with that 10 watt UV. That fish would have been dead before it could have even reduced the parasite load by any considerable amount.

 

25 watt isn't the most attractive solution 😉 but if you want dino dead...like .. yesterday that is how to do it on a small tank.

 

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[mcarroll]

18 hours ago, Tamberav said:

but Ostreopsis is not the same as Amyloodinium.

Lifestyle difference, true...they keep to the sand bed and don't venture (much) into the water.

 

18 hours ago, Tamberav said:

You nailed the install in that pic.  Nice!  🙂 

 

And it's true that the move UV you apply, the better – guidelines are minimums.....but as your picture illustrates, there are some practical limits.

 

 

 

[second_decimal]

19 hours ago, Tamberav said:

but Ostreopsis is not the same as Amyloodinium. I know velvet can overwhelm a fish fast. If I had been trying to treat velvet with that 10 watt UV. That fish would have been dead before it could have even reduced the parasite load by any considerable amount.

 

good grief... for a moment i was almost ready to buy the IM 9w uv but with this additional info, I'm glad I didn't. Looks like i will have to plumb in something a little more powerful.