Is UV actually viable for parasite management?

[Randy Holmes-Farley Verified Community Expert]

How can it be "beyond normal human comprehension" and then you express it right after the comma ?

I think my point is self explanatory, and see no point in debating it. I can easily express a number bigger than the number of atoms in the universe, but that number is too large for a person to have a grasp on what it means from a human perspective.

 

[Randy Holmes-Farley Verified Community Expert]

Did “we” all take it? Does it even “work” some of the time? Science, very loose term when it comes to the jab, has no clue what it actually does and doesn’t do.

Science does have a good understanding of what UVC does though.

Whether the science stands up for some in here is irrelevant to me and likely most hobbyists. Some very large and well known breeders will tell you how much healthier their fish are when it’s in use. The science of why makes no difference.

Kind of like Prime and whether or not it works. The scientists on here will tell you it can’t and doesn’t work. Those ACTUALLY using will tell you it saves lives of millions of fish and you can clearly see it work. The largest fish breeders in the world use it routinely to save fish. But the scientists with no real world application will sit and argue about how “it can’t work.”

It really is a giant waste of time to go back and forth with a few users on here. Multiple are in this thread

While not the point of this thread, there are some seriously misleading comments there, IMO.

Do you really believe that we have no clue whether the Covid vaccines reduce hospitalizations and deaths?

It’s been studied far more extensively than UV sterilizers.

The Prime comments also are misleading, IMO,. There’s not a single blinded study to show that Prime works, while COVID has them.

 

[Jay Hemdal Verified Community Expert]

In a scenario where the UV was plumbed into a closed loop under the display tank…is the "side stream" factor negated ?

If the UV unit is large enough to maintain the manufacturers suggested flow for addressing parasites, while passing 100% of the return flow thru the UV…does the discussion change?

The different portions of the discussion seems to have drifted from the OP’s question and fallen down into .1%, kill vs neuter, etc. Large companies, motivated by profit, do not invest in technology that does not have a good return on investment. From the information available to me, it seems that most of the commercial operations centered around marine fish use UV.

The COVID vaccine does t work every time, but we all took the Jab. UV may not work every time, but those who argue over the last .1% of water and give an example of a reef aquarium with stratified layers and uncirculated areas of water are just arguing for arguments sake and seem to be missing the point.

Just my opinion. I’m probably wrong.

I woke up at 6 am this morning with an epiphany of a good example of how UV sterilizers don't work on a side stream;

Take into consideration two type of fisheries; flow-through raceways and open sea cages.

In both of those cases, there is incoming new water constantly bathing the fish that is in essence not carrying many, (if any) disease propagules. Yet, in both situations, epizootics are common. Why is that? It is because despite the influx of new water (or UV sterilized water in our case) the diseases are able to propagate inside the chamber itself, moving fish to fish, or on a single fish itself, without ever being flushed out. Nitrogenous wastes ARE kept out of these systems, so it isn't from lack of flow. The diseases present run the complete gamut; viral, bacterial, protozoan and even some metazoans.

Certainly these intensive culture systems have high biomass, much greater than in the open sea, but so do our aquariums.

 

[Freenow54]

I'd be happy to read a reference or two on it (I have Noga's book if it's in there) if you have the time to point me towards them, but the point I was trying to make is not that the side stream effect isn't important, but that it already happens within the tank. That makes it hard for me to imagine a way to even quantify the effects of some of the flow bypassing the UV and attribute the problem to the UV bypass. Perhaps there's a study that directly compared the two on a recirculating system that I haven't seen. I just think when you consider all of our different combinations of pumps, tanks, plumbing, powerhead directions, etc...it's hard to point the finger at a UV bypass for me. Continued below though, linearly...


This part is pretty true, although it appeared on the most-recent page I saw, and that explains the misunderstanding. I totally posted in this thread long ago, saw it show up on my feed when I had 10 spare minutes, read the latest page and the one before it, and said tl;dr to the rest. I've gone back now though. You spent pages (and perhaps hours) agreeing with my point. I was reading side-stream as simply a bypass on the UV, which is something many of us use to control flow to the unit without impeding total system flow. My error. The effect happening in the tank was my point, so I think I just miscommunicated what I was talking about. While I saw "side-stream" as a UV bypass, others were triggered from prior conversations where it was used differently. Lmk if I'm misinterpreting the situation.


This part is a little different though. Polishing isn't the only goal on pools - there are pathogenic microbes in that water that need to be addressed (e.g. E. coli from dirty butts, which has published standards and the UVs are tested for it). They can't say that you can lower your chlorine concentration by using this product without such testing, of course. So when I initially read your justification for how they're different, it sounded like "they're the same. They both check all of the boxes."

Both Pentair versions sport the same performance characteristics as I recall. Both are also sold for freshwater applications to target microbes that overlap both fish and pool industries. Microbes that have published data, and when necessary (hey, that's business) they are tested for.


This part has me confused, but I think I was just unclear again because I didn't check the long history (again) but my point was that all of these are read in Watts, so Watts can be used to express these values, but they are different numbers. I even posted an example. So I think we may be in agreement on this too. I will take responsibility for not reading enough of the prior context, but when it comes to assuming that I'm defending the idea that all of the Wattages are the same just because I quoted your post, then maybe you attributed my thoughts to a prior argument instead of looking at what I was posting numbers for. I went after the whole "A watt only tells us what is consumed, not what the lamp actually outputs" part of your quote. I didn't say that input Wattage tells us the output - I said the opposite. Wattage can tell you multiple things, but you can't derive one Wattage from another, right?

Are we friends now? Lol.

Again the fact I would think is that not all of the offending parasites are free floating again the cycle of a wood tick is relevant here. Assuming they are mindless ( lets hope ) unlike vegetables apparently they drop off the host when they are engorged by blood , a mosquito takes blood and lays eggs in dormant water. Viruses ..........

 

[allenk4]

I woke up at 6 am this morning with an epiphany of a good example of how UV sterilizers don't work on a side stream;

Take into consideration two type of fisheries; flow-through raceways and open sea cages.

In both of those cases, there is incoming new water constantly bathing the fish that is in essence not carrying many, (if any) disease propagules. Yet, in both situations, epizootics are common. Why is that? It is because despite the influx of new water (or UV sterilized water in our case) the diseases are able to propagate inside the chamber itself, moving fish to fish, or on a single fish itself, without ever being flushed out. Nitrogenous wastes ARE kept out of these systems, so it isn't from lack of flow. The diseases present run the complete gamut; viral, bacterial, protozoan and even some metazoans.

Certainly these intensive culture systems have high biomass, much greater than in the open sea, but so do our aquariums.

Good example. Especially the open ocean fisheries.

The water in the open ocean achieves 99.9% turnover within the cage/pen system and the incoming water has some level of disease, native to it.

Seems similar to a closed system that recirculates 99.9% of its water thru a side stream UV and the total water volume in the system still has some level of disease within it.

Neither set-up will "eliminate" disease, both have proven beneficial in reducing the potential impact of a disease like marine ich, by reducing the total population of ich in the fishes environment.

Makes Sense.

"Control the Controllable's" -Julian Rotter

 

[BeanAnimal]

Good example. Especially the open ocean fisheries.

The water in the open ocean achieves 99.9% turnover within the cage/pen system and the incoming water has some level of disease, native to it.

Seems similar to a closed system that recirculates 99.9% of its water thru a side stream UV and the total water volume in the system still has some level of disease within it.

Neither set-up will "eliminate" disease, both have proven beneficial in reducing the potential impact of a disease like marine ich, by reducing the total population of ich in the fishes environment.

Makes Sense.

"Control the Controllable's" -Julian Rotter

You just reframed (actually flipped) what he said back into your 99.9% argument, as if it is now supported and he agrees with you. Your argument has been refuted by numerous credible people in this thread several times. He was telling you that you are still wrong, by example, not agreeing with you.

No, they are not similar at all. An ocean pen exchanges with an unbounded volume. What leaves does not come back. A closed system returns everything to the same water. Those are opposite cases, not similar ones.

You have also ignored the biology again, assuming organisms swimming in the water and amongst the rock and fish mix just like the water they swim in.

That quote is a silly decoration meant to sound conclusive. It has nothing to do with the argument.

 

[Jay Hemdal Verified Community Expert]

Good example. Especially the open ocean fisheries.

The water in the open ocean achieves 99.9% turnover within the cage/pen system and the incoming water has some level of disease, native to it.

Seems similar to a closed system that recirculates 99.9% of its water thru a side stream UV and the total water volume in the system still has some level of disease within it.

Neither set-up will "eliminate" disease, both have proven beneficial in reducing the potential impact of a disease like marine ich, by reducing the total population of ich in the fishes environment.

Makes Sense.

"Control the Controllable's" -Julian Rotter

But that isn’t the point I’m making; flow through systems develop serious epizootics, just like systems with side stream UV do.

 

[Ryan - Serious Reefs]

I often wonder if a broader set of questions would be more useful to the OP.

Is UV actually viable for parasite management?
This usually leads to the familiar circular debate. Often theoretical in nature.

What degree of confidence can you state your opinion with?
Many “facts” are really just beliefs or interpretations.

Any applicational experiences with this topic?
Have you actually used UV? Would you use it again?

I will shoot.

Yes, I believe commercial-grade UV (Pentair) is a viable tool for parasite management in reefing. It does need to be sized, installed, and maintained properly to work. I’m less confident in hobby-grade UV, or that it will consistently be implemented correctly by the casual user.

I’d say I’m about 75% confident. The anecdotal experiences I and my peers have had are compelling, but there are simply too many unknowns to be 100% confident either way. I would be wary of anyone's council on this topic that is 100% confident.

I’ve used UV on many tanks, including those with many known “ich magnets,” and I do believe it has contributed to avoiding serious parasite issues in those systems. I have also seen it prevent/control/solve some forms of dinos. I recommend using the best parasite-management strategy your budget, space, and skill level allow. Personally, I would use UV on any tank where the parasite risk is above average and space allows it to be part of the solution.

 

[Privateye]

I think I posted this in another, similar thread a while back, but I found this article particularly interesting and relevant:

https://www.sciencedirect.com/science/article/pii/S0044848621012618

They tested the UV dose required for sterilizing marine ich in a petri dish, which yielded results similar to the 280 mJ/cm2 dose referenced in earlier literature.

But when they tested UV in a flow-through system with fish, they found that cryptocaryon lost its ability to infect the host around 185 mJ/cm2. With a recirculating system it could be even less UV required if the effects from multiple passes are cumulative, but I'm just speculating about that.

It kind of supports the anecdotal reports from the trade that ich can be eliminated/treated (I'm not trying to open a can of worms based on which word is used here) at doses lower than the published 280 mJ/cm2. Of course, there's always the possibility that another parasite was misidentified as cryptocaryon too.

 

[Ryan - Serious Reefs]

I think I posted this in another, similar thread a while back, but I found this article particularly interesting and relevant:

https://www.sciencedirect.com/science/article/pii/S0044848621012618

They tested the UV dose required for sterilizing marine ich in a petri dish, which yielded results similar to the 280 mJ/cm2 dose referenced in earlier literature.

But when they tested UV in a flow-through system with fish, they found that cryptocaryon lost its ability to infect the host around 185 mJ/cm2. With a recirculating system it could be even less UV required if the effects from multiple passes are cumulative, but I'm just speculating about that.

It kind of supports the anecdotal reports from the trade that ich can be eliminated/treated (I'm not trying to open a can of worms based on which word is used here) at doses lower than the published 280 mJ/cm2. Of course, there's always the possibility that another parasite was misidentified as cryptocaryon too.

For what it is worth the commercial Pentair systems are rated for 180 MJ/CM² which is close to your reference. It's been a while since I researched them but I believe they assume end of bulb life and some level of turbidity.

Below is why I am Iess trustful of UV marketed to hobbyists. Aqua UV is intentionally running much lower dosages which allows for smaller sized more affordable units. There is a claim that it is better for the tank but is it even effective at the intended goal then?

Pentair 40 watt
Tank Size: Up to 230 gallons
Dose: 180 MJ/CM²
Flow Rate: 157-262 GPH
Dimensions: 43" long . 3.5" body diameter.

AquaUV 40*
Tank Size: Up to 325 gallons
Dose: 90 mJ/cm²
Flow Rate: 967 (min)
Dimensions: 36.875" L x 3.75" body diameter.

*AquaUV Recommendation: A UV rated in the 30,000 or 45,000 µw/cm2 (EOL) is ideal for the reef environment. UV’s used at higher kill rates will destroy the planktonic food supply for the reef. (No reef or live rock) A UV rated in the 75,000 or 90,000 µw/cm2 (EOL) will be the most effective at controlling fish disease.

For what it is worth, the higher dose has never materialized as legit issue in my tanks and I think more FUD or marketing to sell smaller, more attractive, easier to install units.

 

[Privateye]

For what it is worth the commercial Pentair systems are rated for 180 MJ/CM² which is close to your reference. It's been a while since I researched them I believe that assume end of bulb life and assume some level of turbidity.

Below is why I am Iess trustful of UV marketed to hobbyists. Aqua UV is intentionally running much lower dosages which allows smaller sized more affordable units. There is a claim that it is better for the tank but is it even effective at the intended goal then?

Pentair 40 watt
Tank Size: Up to 230 gallons
Dose: 180 MJ/CM²
Flow Rate: 157-262 GPH
Dimensions: 43" long . 3.5" body diameter.

AquaUV 40*
Tank Size: Up to 325 gallons
Dose: 90 mJ/cm²
Flow Rate: 967 (min)
Dimensions: 36.875" L x 3.75" body diameter.

*AquaUV Recommendation: A UV rated in the 30,000 or 45,000 µw/cm2 (EOL) is ideal for the reef environment. UV’s used at higher kill rates will destroy the planktonic food supply for the reef. (No reef or live rock) A UV rated in the 75,000 or 90,000 µw/cm2 (EOL) will be the most effective at controlling fish disease.

For what it is worth, the higher dose has never materialized as legit issue in my tanks and I think more FUD or marketing to sell smaller, more attractive, easier to install units.

I actually used to work at Pentair, sold many UVs, and did tech support too. You're spot-on! They assume 90% UV transmittance as a safety factor, and the dose they report is for a lamp after 1 year of use. The actual dose could be higher prior to then, but since dosages decrease over time they recommend replacing the lamp after 1 year of use because it may no longer deliver the advertised dose (though it still may still illuminate and work for a customer's purposes). Saltwater systems tend to have good UV transmittance, but freshwater can vary widely. The lowest I saw was 4%. We didn't recommend UV sterilizers at all below a UVT of 75-85% (I forget the exact number - it's been a while). Turbidity is a factor for sure, but certain dissolved metals scatter the UV light too, especially iron. You see horrible UVT in hydroponic and aquaponic systems where iron is dosed. Iron has low solubility in salt water though.

Aqua UV recommends a lower dose for parasites than Pentair, but that could be more of a freshwater thing. Freshwater ich takes 105 mJ/cm2 to sterilize according to literature. 90 mJ/cm2 might work well enough for their units if determined through internal testing. Reef aquariums are a relatively-new market for UV when compared to koi ponds, so there's still a lot of koi pond sizing info out there.

I also feel that destroying the planktonic food supply is not a big issue. It feels like teleology when compared to my experience. We're mostly dealing with photosynthetic symbionts, and I've seen commercial-sized coral systems running UV in excess of 500 mJ/cm2. It feels kind of like saying your duncans or hammers will die if you don't target feed them. Trust me, they'll do just fine with just light (duncans will definitely grow faster with some feed though).

I also don't know how Aqua UV's lamp performance is rated so much higher than Pentair's (at a given flow rate), yet they don't seem to yield the same customer satisfaction. I know Aqua assumes 100% UVT (and it's not a linear trend - that's a notable difference in dose from 90% UVT but I don't remember how much) but even that doesn't explain all of it. Maybe it's other safety factors Pentair has that I'm not aware of, or something else. I don't recall the lamp type for Aqua UV but if it is an amalgam lamp (possible) or a medium-pressure lamp (unlikely) then maybe it could deliver a higher UV dose than a low-pressure lamp at a given wattage.

One thing I always felt I could stand by though was Pentair's numbers. They have safety factors all over the place based on internal testing. The original Sweetwater blowers are a great example. Pentair posts conservative performance numbers, and that results in people calling in with things like "I just bought this bait store, and my whole operation runs on this blower. I don't know what model it is but it looks like it's been here a while. I think I should have a spare."

I determined the model based on the dimensions. Management determined it was 35-40 years old based on the label address and font. I ran into situations similar to this several times a year with just that product line alone.

 

[Ryan - Serious Reefs]

I won't claim to know which is right but the differences between AquaUV and Pentair have always interested me. Typically the same watt bulb but the Aqua UV is materially smaller form factor, way higher flow rates, and way lower µw/cm2 recommendations.

One thing thats always troubled me is both the AquaUV 15 watt hang on and the 15 watt classic rated for a 75 gallon tank. They can't have the same contact time because the classic is dramatically bigger than the hang on and the suggested flow rate is almost identical 214 vs 233 GPH. Seems very unlikely that both would be rated for a 75 gallon tank. I asked at a RAP and they acknowledged the contact time issue but just told me the owner assures them that both work

There is a lot of snake oil type undersized UV in our hobby where the goal isn't to work, only to sell you something. I don't know if I would go as far as to say AquaUV fits that but what they are rated for does seem to fall in between the commercial ratings and the entry level toys.

 

[BeanAnimal]

That sounds about right.

"The owner assures me it works"

That is exactly the issue between an engineered commercial/industrial solution verified to meet a standard and/or pass a specific test vs "hobby grade".

 

[ReefED!]

I won't claim to know which is right but the differences between AquaUV and Pentair have always interested me. Typically the same watt bulb but the Aqua UV is materially smaller form factor, way higher flow rates, and way lower µw/cm2 recommendations.

One thing thats always troubled me is both the AquaUV 15 watt hang on and the 15 watt classic rated for a 75 gallon tank. They can't have the same contact time because the classic is dramatically bigger than the hang on and the suggested flow rate is almost identical 214 vs 233 GPH. Seems very unlikely that both would be rated for a 75 gallon tank. I asked at a RAP and they acknowledged the contact time issue but just told me the owner assures them that both work

There is a lot of snake oil type undersized UV in our hobby where the goal isn't to work, only to sell you something. I don't know if I would go as far as to say AquaUV fits that but what they are rated for does seem to fall in between the commercial ratings and the entry level toys.

The HOB one helped me get rid of Ostreopsis when plumbed directly into my 180g display, while my 57w sump plumbed one wasn't helping.

Greatly undersized for the tank but I figured that specific use case was a "some is better than nothing" situation and it turned out to be correct.

It's possible it was a placebo effect but Ostreopsis isn't one you want to play around with because it's so toxic so I'd do it again in a heartbeat.

 

[allenk4]

I actually used to work at Pentair, sold many UVs, and did tech support too. You're spot-on! They assume 90% UV transmittance as a safety factor, and the dose they report is for a lamp after 1 year of use. The actual dose could be higher prior to then, but since dosages decrease over time they recommend replacing the lamp after 1 year of use because it may no longer deliver the advertised dose (though it still may still illuminate and work for a customer's purposes). Saltwater systems tend to have good UV transmittance, but freshwater can vary widely. The lowest I saw was 4%. We didn't recommend UV sterilizers at all below a UVT of 75-85% (I forget the exact number - it's been a while). Turbidity is a factor for sure, but certain dissolved metals scatter the UV light too, especially iron. You see horrible UVT in hydroponic and aquaponic systems where iron is dosed. Iron has low solubility in salt water though.

Aqua UV recommends a lower dose for parasites than Pentair, but that could be more of a freshwater thing. Freshwater ich takes 105 mJ/cm2 to sterilize according to literature. 90 mJ/cm2 might work well enough for their units if determined through internal testing. Reef aquariums are a relatively-new market for UV when compared to koi ponds, so there's still a lot of koi pond sizing info out there.

I also feel that destroying the planktonic food supply is not a big issue. It feels like teleology when compared to my experience. We're mostly dealing with photosynthetic symbionts, and I've seen commercial-sized coral systems running UV in excess of 500 mJ/cm2. It feels kind of like saying your duncans or hammers will die if you don't target feed them. Trust me, they'll do just fine with just light (duncans will definitely grow faster with some feed though).

I also don't know how Aqua UV's lamp performance is rated so much higher than Pentair's (at a given flow rate), yet they don't seem to yield the same customer satisfaction. I know Aqua assumes 100% UVT (and it's not a linear trend - that's a notable difference in dose from 90% UVT but I don't remember how much) but even that doesn't explain all of it. Maybe it's other safety factors Pentair has that I'm not aware of, or something else. I don't recall the lamp type for Aqua UV but if it is an amalgam lamp (possible) or a medium-pressure lamp (unlikely) then maybe it could deliver a higher UV dose than a low-pressure lamp at a given wattage.

One thing I always felt I could stand by though was Pentair's numbers. They have safety factors all over the place based on internal testing. The original Sweetwater blowers are a great example. Pentair posts conservative performance numbers, and that results in people calling in with things like "I just bought this bait store, and my whole operation runs on this blower. I don't know what model it is but it looks like it's been here a while. I think I should have a spare."

I determined the model based on the dimensions. Management determined it was 35-40 years old based on the label address and font. I ran into situations similar to this several times a year with just that product line alone.

Great Information

Thank You