Is UV actually viable for parasite management?

[allenk4]

That is one of several paradoxes described by Zeno. It describes asymptotic approach, which is evident in the ideal model. It says nothing about whether the ideal model describes a fish tank.

Here is what reality actually says:

Reality is a tank with rock, non-uniform flow, and motile organisms that are not evenly distributed. That is what your argument had to survive, and it didn't.

Whether the gap between 99.9% and 100% is meaningful was never the issue.

The model is not reality. The calculator is the best case and it still didn't hold. Theronts don't distribute like water regardless of what the turnover figure says.

The either/or you set up was broken logic, and the citation wasn't in the article you linked, which had nothing to do with this argument to begin with.

Using n-turn tank mixing math does not account for exposure rates of unevenly distributed organisms in a real world fish tank.

I agree in principle, that everything you stated is potentially true.

Everything I have stated is potentially true as well.

Do the chemicals added to a reef tank fully circulate?

 

[Jay Hemdal Verified Community Expert]

Great input

You use the word "kill". It’s my understanding that the role of UV is to disrupt the reproductive cycle.

When you say "hobbyist sized units"; is that defined by the wattage vs system volume? Do you have a suggestion that differs from the guidance provided by Pentair and/or Aqua UV ?

Thanks in Advance.

“Kill” can mean direct death, or reproductive impairment. However, in most cases, they measure the actual death of the organism (kill rate).

All UV manufacturers overstate the ability of their products to kill parasites, it’s just part of their sales pitch.

I can't recall if I posted this on this thread or not, I looked back a bit and didn't see it (I'm juggling too many threads ATM).

Here is my write-up regarding UV from my (unpublished) fish disease manuscript:

UV sterilizers

Ultraviolet (UV) sterilizers are also sold as a “cure” for Cryptocaryon. The problem is that most hobbyist-sized UV sterilizers do not have the power to make an effective kill on the relatively large Cryptocaryon parasite. Additionally, UV sterilizers are effective only on the tomite/theront stage, as this is the only point where the parasite is even present in the water column.

For velvet, Amyloodinium, the fallacy here is that tomites/theronts must leave the fish. Actually, some of them may get caught up in the fish’s mucus and stay attached until they become infective trophonts again. For Cryptocaryon, the tomites/theronts do seem to need to leave the fish, but with side stream application of UV (where only a portion of water passes through the unit) DWELL TIME becomes the limiting factor. Only a portion of the theronts are killed before enough of them attach to the fish to continue the infection. This means that UV sterilization will not eliminate active Cryptocaryon infections from a single aquarium. Where it does have benefit is in eliminating tomites as they pass through a filtration system from one discrete tank to another (like in a public aquarium or fisheries lab). Decades ago, diatom filters were touted as cures for ich and velvet. The same issue applies with them; there are adherent forms of these protozoans that can continue to infect the fish without ever having to leave the fish’s body. Even if they do, the same “dwell time” factor means that some theronts will still be present in the water column to infect the fish.

A recent study (Ge-Ling, 2022) indicates that the UV dose required to kill Cryptocaryon theronts/tomites is 185,000 uw/S/cm2. They do go on however, to conclude: “ …both ozone and UV are ineffective in controlling infection within an individual aquarium because of the adhesive nature of C. irritans tomonts (Ma et al., 2017). Therefore, the focus on UV and ozone treatment should prevent live theronts flow into aquaculture ponds. Second, the tomonts are strongly resistant to UV or ozone than theronts, implying that recommended production doses cannot wholly kill tomonts….”

 

[BeanAnimal]

I agree in principle, that everything you stated is potentially true.

Everything I have stated is potentially true as well.

Do the chemicals added to a reef tank fully circulate?

No, we were not both partially right. You were demonstrably wrong, and no amount of dithering is going to resolve that. Not Zeno, not pivoting to chemicals, not recasting it as a rounding argument.

The citation you quoted does not exist in the article you linked, and the article itself has no relevancy here.

The either/or you set up was broken logic.

The calculator does not describe an aquarium.

Those are not matters of principle or potential truth.

Dissolved chemicals distribute reasonably well. They are dissolved. No motility, no behavior, no life cycle. That is a different problem entirely, and it is not the subject or context of this thread. The question is a diversion.

Theronts are not dissolved chemicals. Jay just said the same thing from the biology side. They emerge inches from sleeping fish and attach without ever going near the intake.

 

[ReefED!]

I'm at the point where I question the usefulness of hobby grade UV sterilizers in our systems vs the cost and hassle of setting them up.

I'm not sure that I'd put one on my next system. I suppose they might be good at helping clean up medications, but I've never had algae/bacterial blooms that would require one.

 

[rtparty]

eDNA is not reliable in my experience.

I've seen systems with confirmed low grade ich return as "not detected" in one aquabiomics and two dxaquaria tests.

As far as UV - I'm sure it helps but I bet it depends greatly on size and how it's plumbed - much like how Ostreopsis seems to be resistant to UV until you plumb it directly into the display tank.

(FWIW I ran UV in a system with ich and had no issues until I did with a sensitive fish. )

I’ve successfully used UV twice to deal with Ostreopsis and neither time did I plumb it into the display tank. It’s amazing how quickly it slows and eradicates them

 

[allenk4]

No, we were not both partially right. You were demonstrably wrong, and no amount of dithering is going to resolve that. Not Zeno, not pivoting to chemicals, not recasting it as a rounding argument.

The citation you quoted does not exist in the article you linked, and the article itself has no relevancy here.

The either/or you set up was broken logic.

The calculator does not describe an aquarium.

Those are not matters of principle or potential truth.

Dissolved chemicals distribute reasonably well. They are dissolved. No motility, no behavior, no life cycle. That is a different problem entirely, and it is not the subject or context of this thread. The question is a diversion.

Theronts are not dissolved chemicals. Jay just said the same thing from the biology side. They emerge inches from sleeping fish and attach without ever going near the intake.

Wouldn’t the motility, you mention, during the pelagic Theront increase the chance something would pass thru a UV ?

Do the fish that are most susceptible to Ich actually sleep in the sand where the Ich Tomonts reside ?

Is your argument that a molecule of magnesium is more likely to pass thru a UV than a Theront in the same aquarium?

All these questions of 100% vs 99.9%….chemical vs Theront, etc. etc. Stretching the boundaries of basic logic to make your point. If you don’t think UV has any effect on improving outcomes for marine fishes in a closed system with the presence of Ich, just say so. All the idiots in commercial aquaculture of fish for food and the aquarium hobby are clearly wasting their resources.

 

[allenk4]

I'm at the point where I question the usefulness of hobby grade UV sterilizers in our systems vs the cost and hassle of setting them up.

I'm not sure that I'd put one on my next system. I suppose they might be good at helping clean up medications, but I've never had algae/bacterial blooms that would require one.

What specific UV do you consider "hobby grade" ?

What variables are considered?

Isn’t all of the equipment used by reef hobbyists considered "hobby grade"?

It seems the units offered by Saltwater.com and BRS from Aqua UV and Pentair should be effective, when the proper wattage and flow are utilized for the specific system.

Pentair UV specifically is widely used in applications where if it didn’t work, humans would get sick…lawsuits would be filed….

 

[Dr. Jim]

I haven't read all these posts, but as a veterinarian with a special interest in fish and coral diseases, I'd like to respond to the OP. I think there are two areas that need to be discussed:

1) Should a system be run with UV 24/7?
2) And, if so, would that assure one that his/her powder blue will not get Ich?

I'd say "no" to both. Of course there are many successful systems with 24/7 UV but it can also be assumed that the UV might be both helpful and harmful. For me, I don't want to kill off anything beneficial to my corals (e.g. bacterioplankton and other beneficial micro-organisms) even if that unknown amount is slight. My more important belief is that the UV won't make any difference regarding whether or not your Powder Blue will break out with Ich (or other parasites).

I've been quarantining and treating batches of fish, mostly from wholesalers, for over 40 years. I can safely say that I've NEVER had a batch of fish where no parasites were present. (I understand that the incidence of parasites is undoubtedly higher in newly imported fish than from stores, but probably not by much unless the store properly quarantines and treats). Although I do use UV on my Q-tanks, I am certain that UV alone, without meds, would be futile in a quarantine/treatment situation). I've learned, long ago, to treat every new fish for every possible parasite. By doing this, I have had parasite-free tanks for decades. (I even feed food laced with meds for intestinal worms and protazoa although I will admit this is hit or miss, but probably helps and is easy to do).

Here is a video of my present Powder Blue. (BTW, I've had several PB's in various tanks over the years and never had any hint of aggression problems like is written about so often).

 

[BeanAnimal]

Wouldn’t the motility, you mention, during the pelagic Theront increase the chance something would pass thru a UV ?

Answer: No

And, your question (whole post) doesn't pass the sniff test. You already acknowledged Jay's answer, in this thread just a few posts ago, in your own words.

Then, to paint the picture that your argument still has a surviving chance, you blatantly ignore Jay's post and the already clear context of "motility" to ask a question that was already answered directly and contextually numerous times above.

They are not swimming toward the intake and they are not evenly distributed. They are swimming toward hosts. They are photo and chemo sensitive, wired to find nearby hosts. That is directed movement, the opposite of the uniform distribution your argument requires. They are not distributed like a dissolved substance, which is the whole point. Continued reframes aren't going to save your failed arguments.

Do the fish that are most susceptible to Ich actually sleep in the sand where the Ich Tomonts reside ?

That is a red herring, and the premise is also wrong. Tomonts encyst on rock, glass, and equipment, not just sand. Jay's point doesn't require a fish sleeping in the substrate. It requires a theront emerging near a resting fish, which can happen anywhere in the tank.

Is your argument that a molecule of magnesium is more likely to pass thru a UV than a Theront in the same aquarium?

Yes. A magnesium ion is more likely to be evenly distributed. It has no behavior, it goes where the water goes. A theront doesn't. Some certainly pass through, but their transit isn't governed by the turnover figure, which is why that figure tells you nothing about exposure.

All these questions of 100% vs 99.9%….chemical vs Theront, etc. etc. Stretching the boundaries of basic logic to make your point. If you don’t think UV has any effect on improving outcomes for marine fishes in a closed system with the presence of Ich, just say so. All the idiots in commercial aquaculture of fish for food and the aquarium hobby are clearly wasting their resources.

Nothing was stretched, that is rewriting what actually happened. Every point came straight out of your own posts and was cleanly refuted. You made specific claims, pushed them authoritatively, and could not back them.

I didn't say or imply UV was useless. I made it clear several times now that our engagement is about your claims regarding guaranteed exposure in n-time based on flow rate and tank volume.

I said your claims and the arguments used to support them were wrong, and I broke each one. The 100%, the calculator, the dithering, hiding behind Zeno, the either/or, and the citation that isn't in the article you linked, which wasn't relevant to begin with. All of it. Randy refuted your argument, and so did Jay.

 

[BeanAnimal]

What specific UV do you consider "hobby grade" ?

Here, the term "hobby grade" denotes build quality, the unit's actual power and size, and the sizing guidance behind it. See Jay's post above and do your own math. Note his point about manufacturers overstating parasite kill ability.

What variables are considered?

Goal (target organisms), flow requirements, system volume, lamp power, unit dimensions, biological load. All of the things that break your ideal flow model assumptions. Initial cost, lamp lifetime and replacement cost. Heat added to the system. There are numerous variables. Each person will have a different value assignment and criteria as to what makes sense and what doesn't with regard to cost vs effectiveness and goals.

Isn’t all of the equipment used by reef hobbyists considered "hobby grade"?

No. That is equivocation. Using "hobby grade" to mean owned by hobbyists so you can ignore the context that Jay used, which is insufficient power for the job.

It seems the units offered by Saltwater.com and BRS from Aqua UV and Pentair should be effective, when the proper wattage and flow are utilized for the specific system.

Pentair UV specifically is widely used in applications where if it didn’t work, humans would get sick…lawsuits would be filed….

Jay just gave the number. 185,000 µW·s/cm² to kill Cryptocaryon theronts, from Ge-Ling 2022. Stated above with direct citation.

"Specific system" is doing a lot of work here. If you mean volume and flow, that's the turnover argument again, and it's the thing that has been wrong from the start, because it ignores real world systems. We don't have a simple model for that. Moreover read Jay's post carefully regarding dwell time.

He also said manufacturers overstate parasite performance as part of the sales pitch, and that dwell time is the limiting factor in side-stream applications.

The Pentair comparison is a fallacy. Municipal water treatment and commercial/industrial food safety and a reef tank are not equivalent. The targets, required doses, sizing and flow configurations are all different. Hobby marketed vs engineered solutions.

 

[allenk4]

Answer: No

And, your question (whole post) doesn't pass the sniff test. You already acknowledged Jay's answer, in this thread just a few posts ago, in your own words.

Then, to paint the picture that your argument still has a surviving chance, you blatantly ignore Jay's post and the already clear context of "motility" to ask a question that was already answered directly and contextually numerous times above.

They are not swimming toward the intake and they are not evenly distributed. They are swimming toward hosts. They are photo and chemo sensitive, wired to find nearby hosts. That is directed movement, the opposite of the uniform distribution your argument requires. They are not distributed like a dissolved substance, which is the whole point. Continued reframes aren't going to save your failed arguments.


That is a red herring, and the premise is also wrong. Tomonts encyst on rock, glass, and equipment, not just sand. Jay's point doesn't require a fish sleeping in the substrate. It requires a theront emerging near a resting fish, which can happen anywhere in the tank.


Yes. A magnesium ion is more likely to be evenly distributed. It has no behavior, it goes where the water goes. A theront doesn't. Some certainly pass through, but their transit isn't governed by the turnover figure, which is why that figure tells you nothing about exposure.



Nothing was stretched, that is rewriting what actually happened. Every point came straight out of your own posts and was cleanly refuted. You made specific claims, pushed them authoritatively, and could not back them.

I didn't say or imply UV was useless. I made it clear several times now that our engagement is about your claims regarding guaranteed exposure in n-time based on flow rate and tank volume.

I said your claims and the arguments used to support them were wrong, and I broke each one. The 100%, the calculator, the dithering, hiding behind Zeno, the either/or, and the citation that isn't in the article you linked, which wasn't relevant to begin with. All of it. Randy refuted your argument, and so did Jay.

Those are some very strong swimming Ich Theronts you have there. Not being blown about and spread through the tank by wave makers and return flow…just swimming straight to their targeted victim. I had no idea.

 

[allenk4]

Here, the term "hobby grade" denotes build quality, the unit's actual power and size, and the sizing guidance behind it. See Jay's post above and do your own math. Note his point about manufacturers overstating parasite kill ability.


Goal (target organisms), flow requirements, system volume, lamp power, unit dimensions, biological load. All of the things that break your ideal flow model assumptions. Initial cost, lamp lifetime and replacement cost. Heat added to the system. There are numerous variables. Each person will have a different value assignment and criteria as to what makes sense and what doesn't with regard to cost vs effectiveness and goals.


No. That is equivocation. Using "hobby grade" to mean owned by hobbyists so you can ignore the context that Jay used, which is insufficient power for the job.


Jay just gave the number. 185,000 µW·s/cm² to kill Cryptocaryon theronts, from Ge-Ling 2022. Stated above with direct citation.

"Specific system" is doing a lot of work here. If you mean volume and flow, that's the turnover argument again, and it's the thing that has been wrong from the start, because it ignores real world systems. We don't have a simple model for that. Moreover read Jay's post carefully regarding dwell time.

He also said manufacturers overstate parasite performance as part of the sales pitch, and that dwell time is the limiting factor in side-stream applications.

The Pentair comparison is a fallacy. Municipal water treatment and commercial/industrial food safety and a reef tank are not equivalent. The targets, required doses, sizing and flow configurations are all different. Hobby marketed vs engineered solutions.

Watts are Watts….right ?

 

[Jay Hemdal Verified Community Expert]

Those are some very strong swimming Ich Theronts you have there. Not being blown about and spread through the tank by wave makers and return flow…just swimming straight to their targeted victim. I had no idea.

The point is that enough theronts reach a fish and manage to attach to it to negate much of the value of a sidestream UV system.

 

[BeanAnimal]

Watts are Watts….right ?

Context always matters, you are attempting false equivalency again.

A watt only tells us what is consumed, not what the lamp actually outputs. Consider ballast topology and lamp drive, lamp quality and spectrum, and the lamp’s age.

Now add those variables to the UV chamber volume and configuration, lamp dimensions, flow rate, dwell time, distance from the lamp, etc.

All of that goes into what the overall dose is. Read Jay's response regarding dose and dwell time and put it all together.

Engineered solutions vs hobby marketed, which Jay touched on as well.

Those are some very strong swimming Ich Theronts you have there. Not being blown about and spread through the tank by wave makers and return flow…just swimming straight to their targeted victim. I had no idea.

That's a straw man supported by mocking. I said they aren't evenly distributed and they respond to light and host cues. Neither requires them to swim in a straight line. This was also clearly and contextually answered several times above. A uniform or ideal mixing model doesn't hold. Also see Jay”s post above, it further breaks your argument.

Each of your responses is another pivot from one fallacy derived argument to the next, ignoring the refutations already given by me, Randy, Jay and others.

 

[13rodo]

Correct me if I’m wrong here, but isn’t the theory behind a UV to keep populations closer to a concentration that might be observed in the wild as opposed to complete eradication (or even close to complete)? In other words management as opposed to curing?

If that’s the case, at best it’s helpful and at worst it’s snake oil that doesn’t really impact much due to the dynamics being discussed. I guess what I’m saying is it can’t hurt as long as the user understands that its purpose isn’t elimination.

Full disclosure… I buy into Paul’s natural immunity and am starting a white worm culture myself. But I also don’t see how a UV hurts anything other than your wallet and maintenance.

 

[BeanAnimal]

But I also don’t see how a UV hurts anything other than your wallet and maintenance.

I am not going to wade into the post other than to ask, if it has any effectiveness against anything, how would it discriminate “good” from “bad”? Does it hurt anything? I suppose the answer depends on perspective and goals.

 

[13rodo]

I am not going to wade into the post other than to ask, if it has any effectiveness against anything, how would it discriminate “good” from “bad”? Does it hurt anything? I suppose the answer depends on perspective and goals.

It can’t obviously. But if it limits some good it is reasonable to assume it also limits some bad. Or it limits neither.

Edit: For clarity, “good” and “bad” in the statement are meant to encompass anything that could be seen as a net benefit/detriment (bacteria, algae, etc).

 

[Randy Holmes-Farley Verified Community Expert]

Yes. A magnesium ion is more likely to be evenly distributed. It has no behavior, it goes where the water goes. A theront doesn't. Some certainly pass through, but their transit isn't governed by the turnover figure, which is why that figure tells you nothing about exposure.

We also do not care or know if some fraction of ions like magnesium never pass through. They are evenly mixed.

 

[BeanAnimal]

We also do not care or know if some fraction of ions like magnesium never pass through. They are evenly mixed.

Ahh, yes I wish I would have thought of that approach. You certainly can narrow quickly to what matters with more clarity than my rambling.

 

[ReefED!]

Correct me if I’m wrong here, but isn’t the theory behind a UV to keep populations closer to a concentration that might be observed in the wild as opposed to complete eradication (or even close to complete)? In other words management as opposed to curing?

If that’s the case, at best it’s helpful and at worst it’s snake oil that doesn’t really impact much due to the dynamics being discussed. I guess what I’m saying is it can’t hurt as long as the user understands that its purpose isn’t elimination.

Full disclosure… I buy into Paul’s natural immunity and am starting a white worm culture myself. But I also don’t see how a UV hurts anything other than your wallet and maintenance.

It's so hard to test to know if it helps at all, but I'm personally of the opinion that it doesn't help enough to justify the cost and setup etc.

That's because I ran fallow, had an eDNA test claim no cryptocaryon detected, introduced my fish that had been QT'd for 40+ days in copper and saw spots on a hippo tang within a week.

Ran another eDNA test, results said not detected, figured it was just hippos being goofy and introduced a clean hybrid powder tang only to see him break out with ich within 1 week (which then spread further to the hippo tang).

Pulled the two symptomatic fish, QT'd, then reintroduced 3 weeks later after another eDNA test claimed no ich again (which I knew was false because I didn't run fallow) and once again the hybrid powder tang developed symptoms within a week.

All this happened while running UV - maybe 57w isn't enough for my 220 total system volume, maybe it's because I had it plumbed on one of the dual returns.

I just know that - for me - I used to believe UV controlled ich and now I don't. My low grade presence should be the ideal candidate for UV to suppress.

The tank is fine now, I Just don't keep acantharus tangs in it. YMMV.