Is UV actually viable for parasite management?

[sixty_reefer]

I don’t agree, and think it is the appropriate and exactly correct mathematical model if the UV kills everything. The inlet of the uv is exactly like the tank outlet and the uv
Output is exactly like the tank input with zero pathogens in it.

Thank you

 

[Randy Holmes-Farley Verified Community Expert]

So is this why James Bond insists on his martinis being shaken, and not stirred? “Stirred martini syndrome” where not all vermouth gets mixed in? Is there a shaken tank model?

Probably. lol

 

[sixty_reefer]

I wonder if you could add dye to the water that could be removed by a separate filter in series with the UV . Myself I made and believe the statement that all the water cannot pas through the UV . I also believe that any organisms will happily attach themselves to the rock or substrate to Complete their cycle . Wood Ticks do it. They feed from say a moose which uses the same paths constantly the tick attaches itself feeds on the moose and then detaches itself to lay eggs on grasses ect. Then the process begins again . Maybe that's how the fish get infected (by direct contact )

To be honest, I usually don’t get involved in equipment discussions. One side says it’s necessary, the other says it’s not and I’m usually somewhere in the middle thinking both sides have valid points. I don’t really see these discussions as having a right or wrong side. Most of the time they’re just about different trade offs, different goals and personal beliefs. For me the interesting part is understanding those trade offs rather than trying to prove one side is universally right.

The only reason I got involved here was because I wanted clarification on one of Randy’s comments.

 

[allenk4]

Depending on size of UV. However I supplement dosing H2o2 and have had good results with the health of my Tangs since starting it as the fish have not had outbreaks of Ich since.

In your opinion…would implementation of Ozone serve the same purpose, as it also acts in the same way as hydrogen peroxide as an oxidizer ?

 

[Randy Holmes-Farley Verified Community Expert]

In your opinion…would implementation of Ozone serve the same purpose, as it also acts in the same way as hydrogen peroxide as an oxidizer ?

FWIW, most people using ozone do not use enough for a long enough contact time to kill bacteria. I expect parasites are even harder to kill, but do not have such data.

 

[allenk4]

No, not correct and citing any number would misrepresent what happened.

We are not arguing over 0.1%. That number came from a model that does not apply to an aquarium. There is no number here. What we do know factually is that the model you used cannot produce it.

You stated 100% of the water molecules circulate through every powerhead and pump, no doubt. Randy corrected that. Your own cited calculator reference returned 99.9%, which contradicts that claim, but it doesn’t end there.

The calculator assumes a single fixed quantity added at time zero and instantaneous, uniform mixing: where whatever re-enters from the pump (filter) on each pass is distributed evenly through the whole volume immediately, and every unit of tank volume has equal probability of being drawn out on the next pass. A reef tank has rock, varied flow, and a reproducing target population. None of it fits the calculator cited.

And theronts are not water molecules. They swim, they respond to stimuli, and are not evenly distributed. A water mixing calculator can’t tell you what fraction of them passes through the UV chamber.

The rest of it, the either/or flow argument you set up, the article you linked, all wrong. There is no 0.1% to argue over because there is no number or fraction to split.

In the real world the problem is complex because every aquarium is different. Different structures, non-uniform flow paths, often with multiple pumps, sumps, skimmers, reactors and other devices that don’t just break the uniform mixing model, they turn it on its head, and that is still outright ignoring the target organisms that are motile, not homogenous with the water.

None of this is to say that UVs can’t be effective at some size and turnover rate. The argument was against your framing of it as a simple n-turns calculation and the absolute and incorrect claims used to support it.

Reality says there is no 100%. You can divide any number by two as many times as you like it will Never reach Absolute Zero…..it’s Infinite Shrinkage.

Stand 10 feet from a wall, move 5 feet closer…then 2.5 feet closer…then 1.25 feet closer. You will never reach the wall.

Hence 99.9%

 

[allenk4]

FWIW, most people using ozone do not use enough for a long enough contact time to kill bacteria. I expect parasites are even harder to kill, but do not have such data.

Thank you for the reply Randy.

Would be an interesting phenomenon to study in a clinical setting, whether elevated ORP has an effect on various parasites, bacteria et al.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you for the reply Randy.

Would be an interesting phenomenon to study in a clinical setting, whether elevated ORP has an effect on various parasites, bacteria et al.

This is some data from my old ozone article:


Reducing Bacteria When Using Ozone

---

Bacteria and other organisms suspended in water can be killed by adequate exposure to ozone. That process is widely used to disinfect drinking water and wastewater in a variety of applications. The doses and exposures of ozone required for disinfection, however, are quite high. They are higher than are used in reef aquarium applications, where typical doses of ozone range up to about 0.3 ppm in typical contact chambers, and last for only a few seconds. Consequently, aquarists must be careful when translating disinfection literature to reef aquarium effects.

In a recent study of a recirculating seawater system,35 the dosing of 0.52 ppm of ozone was tested for its ability to decrease the system's bacterial load. That dose is similar to a 300 mg/hr ozone unit applied to a typical small skimmer flow rate of 150 gallons per hour (568 L/h). In this experiment, the levels of suspended bacteria (both Vibrio and coliform) were analyzed in a variety of locations (intake, pre-ozone, post-ozone, pre-tank, and post-tank). In no case was there a statistically significant reduction in bacteria. Even the addition of a venturi injector to the contact chamber did not adequately help (although it trended toward fewer bacteria, the result was not statistically significant). For comparison purposes, at higher ozone concentrations and contact times (5.3 ppm ozone for 240 minutes), Vibrio vulnificus is easily killed, with fewer than one in a hundred million of the initial bacteria remaining.36

How much ozone, and for how long, is required to kill suspended organisms in seawater? In one study of a suspended dinoflagellate algae (Amphidinium sp. isolated from Australia's Great Barrier Reef), it was found that 5-11 ppm ozone for six hours of exposure was required to kill 99.99% of the organisms.37 While that kill rate is impressive, that exposure is far higher than is ever achieved in a reef aquarium application. Lower doses and shorter contact times had smaller effects. A dose of 2 ppm and a short contact time (with the time not stated in the paper) showed a reduction in bacteria of abut 98% (which is still quite significant, but would not be referred to as disinfection).

Similar results were found for the spores of the bacterium Bacillus subtilis.38 In this case, doses of 14 ppm ozone for 24 hours were required to kill 99.99 percent of the spores. In another study 99.9% of fecal coliforms, fecal streptococci and total coliforms were killed with 10 ppm ozone and a contact time of 10 minutes.39 The exposure of Vibrio species and Fusarium solani (bacteria that are pathogenic to shrimp) to 3 ppm ozone for five minutes killed 99.9% of the bacteria.40Water from a seawater swimming pool was effectively sterilized using 0.5-1.0 ppm ozone in a contact tower.41

The data for the disinfection of freshwater systems are much more extensive, and so include more data at lower contact times and concentrations. In one experiment at a Rainbow trout hatchery, the addition of 1-1.3 ppm of ozone with a contact time of 35 seconds reduced heterotrophic bacteria in the aquarium water itself by about 40-90%.42

Does the ozone used in a typical reef aquarium application reduce bacteria? Maybe, but certainly not to the extent required for disinfection. Still, a reduction of 50% of the living bacteria could have significant effects. The above study in the trout hatchery showed that the use of ozone at several times the typical reef aquarium rate and for about five to ten times the typical contact time results in such a drop. While the data are unavailable, I expect that the bacteria in the water exiting a normal reef aquarium's ozone application are not decreased by as much as 50%.

It seem reasonable to conclude from such literature studies that most bacteria that enter the ozone reaction chamber in a typical reef aquarium application will not be killed by ozone or its byproducts. If killing bacteria in the water column is a goal, then a UV (ultraviolet) sterilizer may be more useful.

Reducing Other Pathogens When Using Ozone

---

There has been extensive analysis of the amount of ozone needed to kill the human pathogen Cryptosporidia parvum in freshwater. Most such studies are looking for significant disinfection, but some data points show the effects at lower doses and contact times, and some researchers have developed models that suggest the amount of killing at any dose/time combination.43 For example, at 22° C approximately 63% of the organisms would be expected to be killed at 1 ppm ozone with a contact time of one minute. The contact times and concentrations are inversely related, so at a contact time of six seconds, the required dose to kill 63% is on the order of 10 ppm ozone. At 0.3 ppm ozone and a six second contact time, typical for the high end of reef ozone applications, less than 5% of the organisms would be expected to be killed.

Many viruses are much easier to inactivate with ozone than are other pathogens.44 Enteric adenovirus, for example, is inactivated to the extent of 99.8% after exposure to 0.5 ppm for 15 seconds.44 Feline calicivirus is inactivated to the extent of 98.6% after exposure to 0.06 ppm for 15 seconds.44Poliovirus type 1 was inactivated to 99% within 30 seconds of contact time at 0.15 ppm ozone.45 Hepatitis A virus was inactivated to the extent of 99.999% within one minute at 1 ppm ozone.46 Norwalk virus was inactivated by 99.9% in 10 seconds of contact at 0.37 ppm ozone.47 Adenovirus type 2 was inactivated by 99.99% by 0.2 ppm ozone with a contact time of about one minute.48

The eggs of a pathogenic helminth (Ascaris suum) were killed to the extent of 90% by exposure to 3.5-4.7 ppm ozone for one hour. One additional hour of exposure killed the remainder.49

It seems reasonable to conclude from such literature studies that many viruses that enter the ozone reaction chamber in a typical reef aquarium application may be killed by ozone or its byproducts. Larger pathogens, however, are likely much more resistant to ozone, and are unlikely to be killed. For such ends, a UV sterilizer may be more useful, but still may not be completely effective.

 

[Paul B]

Stand 10 feet from a wall, move 5 feet closer…then 2.5 feet closer…then 1.25 feet closer. You will never reach the wall.

I just tried that, and now I have a bloody nose.

 

[A_Blind_Reefer]

I just tried that, and now I have a bloody nose.

…..but did you spill your drink?

 

[Jay Hemdal Verified Community Expert]

I had to double check…Saltwater Fish Flukes/monogeneans do indeed have a pelagic stage.

They would be exposed to your UV during this 24-36 hour stage of life.

UV sterilizers are not powerful enough to kill metazoan parasites, including larval fluke Oncomiracidium.

Most/all hobbyist sized units are also incapable of killing Cryptocaryon theronts.

 

[Jay Hemdal Verified Community Expert]

I’ll just make one comment here. In any tank system, not all water passes through the filter system. It’s a classic problem in math called the stirred tank.

If one is adding and removing water from a stirred tank (like a reef aquarium), there is always some water and its contents that is never removed. In this context, that means some never passes through the UV.

Does that matter for using a UV? Probably not, but I wanted to address the assertion made above that 100% of tank water passes through it.

In addition to that, talking specifically about Cryptocaryon theronts, these emerge from the resting tomonts in the early morning, while the fish are sleeping. These can rapidly attach to the fish, only inches away from them, and never get anywhere near the intake for a UV sterilizer.....

 

[Jay Hemdal Verified Community Expert]

1. Never claimed to be a Parasitologist

2. UV is hardly a “Sledgehammer"

3. Cannot confirm without a Tank DNA Test from Aquabiomics

4. Jay Hemdal would agree that with radical measures…Ich can indeed be eliminated. I have previously described the required process

5. I referenced BRS, because they list manufacturer information within their UV product listings

6. Relax

Just to clarify - Cryptocaryon CAN be eliminated from marine aquariums through proper quarantine. We tested our main tropical marine system at the Toledo Zoo, where ALL fish entering it (except some sharks and rays) were quarantined with copper/prazi or hyposalinity. We ran eDNA testing, and after a decade of thousands of fish additions, there is no presence of Cryptocaryon. That takes a lot of work though.

If you are talking about my thread on "ich management", in that I say that I developed that thread, not because it works well, but because the pressure from home aquarists is so great to try to manage it because they feel that treatments take too much work (grin).

https://www.reef2reef.com/threads/ich-management.1028274/

 

[BeanAnimal]

Reality says there is no 100%. You can divide any number by two as many times as you like it will Never reach Absolute Zero…..it’s Infinite Shrinkage.

Stand 10 feet from a wall, move 5 feet closer…then 2.5 feet closer…then 1.25 feet closer. You will never reach the wall.

Hence 99.9%

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.

 

[BeanAnimal]

I just tried that, and now I have a bloody nose.

Then try approaching my precious to put it in a shipping box. I am sure that you can reach it even if you are only 99.999% of the way there.

 

[ReefED!]

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. )

 

[allenk4]

UV sterilizers are not powerful enough to kill metazoan parasites, including larval fluke Oncomiracidium.

Most/all hobbyist sized units are also incapable of killing Cryptocaryon theronts.

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.

 

[allenk4]

Gr

This is some data from my old ozone article:


Reducing Bacteria When Using Ozone

---

Bacteria and other organisms suspended in water can be killed by adequate exposure to ozone. That process is widely used to disinfect drinking water and wastewater in a variety of applications. The doses and exposures of ozone required for disinfection, however, are quite high. They are higher than are used in reef aquarium applications, where typical doses of ozone range up to about 0.3 ppm in typical contact chambers, and last for only a few seconds. Consequently, aquarists must be careful when translating disinfection literature to reef aquarium effects.

In a recent study of a recirculating seawater system,35 the dosing of 0.52 ppm of ozone was tested for its ability to decrease the system's bacterial load. That dose is similar to a 300 mg/hr ozone unit applied to a typical small skimmer flow rate of 150 gallons per hour (568 L/h). In this experiment, the levels of suspended bacteria (both Vibrio and coliform) were analyzed in a variety of locations (intake, pre-ozone, post-ozone, pre-tank, and post-tank). In no case was there a statistically significant reduction in bacteria. Even the addition of a venturi injector to the contact chamber did not adequately help (although it trended toward fewer bacteria, the result was not statistically significant). For comparison purposes, at higher ozone concentrations and contact times (5.3 ppm ozone for 240 minutes), Vibrio vulnificus is easily killed, with fewer than one in a hundred million of the initial bacteria remaining.36

How much ozone, and for how long, is required to kill suspended organisms in seawater? In one study of a suspended dinoflagellate algae (Amphidinium sp. isolated from Australia's Great Barrier Reef), it was found that 5-11 ppm ozone for six hours of exposure was required to kill 99.99% of the organisms.37 While that kill rate is impressive, that exposure is far higher than is ever achieved in a reef aquarium application. Lower doses and shorter contact times had smaller effects. A dose of 2 ppm and a short contact time (with the time not stated in the paper) showed a reduction in bacteria of abut 98% (which is still quite significant, but would not be referred to as disinfection).

Similar results were found for the spores of the bacterium Bacillus subtilis.38 In this case, doses of 14 ppm ozone for 24 hours were required to kill 99.99 percent of the spores. In another study 99.9% of fecal coliforms, fecal streptococci and total coliforms were killed with 10 ppm ozone and a contact time of 10 minutes.39 The exposure of Vibrio species and Fusarium solani (bacteria that are pathogenic to shrimp) to 3 ppm ozone for five minutes killed 99.9% of the bacteria.40Water from a seawater swimming pool was effectively sterilized using 0.5-1.0 ppm ozone in a contact tower.41

The data for the disinfection of freshwater systems are much more extensive, and so include more data at lower contact times and concentrations. In one experiment at a Rainbow trout hatchery, the addition of 1-1.3 ppm of ozone with a contact time of 35 seconds reduced heterotrophic bacteria in the aquarium water itself by about 40-90%.42

Does the ozone used in a typical reef aquarium application reduce bacteria? Maybe, but certainly not to the extent required for disinfection. Still, a reduction of 50% of the living bacteria could have significant effects. The above study in the trout hatchery showed that the use of ozone at several times the typical reef aquarium rate and for about five to ten times the typical contact time results in such a drop. While the data are unavailable, I expect that the bacteria in the water exiting a normal reef aquarium's ozone application are not decreased by as much as 50%.

It seem reasonable to conclude from such literature studies that most bacteria that enter the ozone reaction chamber in a typical reef aquarium application will not be killed by ozone or its byproducts. If killing bacteria in the water column is a goal, then a UV (ultraviolet) sterilizer may be more useful.

Reducing Other Pathogens When Using Ozone

---

There has been extensive analysis of the amount of ozone needed to kill the human pathogen Cryptosporidia parvum in freshwater. Most such studies are looking for significant disinfection, but some data points show the effects at lower doses and contact times, and some researchers have developed models that suggest the amount of killing at any dose/time combination.43 For example, at 22° C approximately 63% of the organisms would be expected to be killed at 1 ppm ozone with a contact time of one minute. The contact times and concentrations are inversely related, so at a contact time of six seconds, the required dose to kill 63% is on the order of 10 ppm ozone. At 0.3 ppm ozone and a six second contact time, typical for the high end of reef ozone applications, less than 5% of the organisms would be expected to be killed.

Many viruses are much easier to inactivate with ozone than are other pathogens.44 Enteric adenovirus, for example, is inactivated to the extent of 99.8% after exposure to 0.5 ppm for 15 seconds.44 Feline calicivirus is inactivated to the extent of 98.6% after exposure to 0.06 ppm for 15 seconds.44Poliovirus type 1 was inactivated to 99% within 30 seconds of contact time at 0.15 ppm ozone.45 Hepatitis A virus was inactivated to the extent of 99.999% within one minute at 1 ppm ozone.46 Norwalk virus was inactivated by 99.9% in 10 seconds of contact at 0.37 ppm ozone.47 Adenovirus type 2 was inactivated by 99.99% by 0.2 ppm ozone with a contact time of about one minute.48

The eggs of a pathogenic helminth (Ascaris suum) were killed to the extent of 90% by exposure to 3.5-4.7 ppm ozone for one hour. One additional hour of exposure killed the remainder.49

It seems reasonable to conclude from such literature studies that many viruses that enter the ozone reaction chamber in a typical reef aquarium application may be killed by ozone or its byproducts. Larger pathogens, however, are likely much more resistant to ozone, and are unlikely to be killed. For such ends, a UV sterilizer may be more useful, but still may not be completely effective.

Great Information. Thank You.

Are you aware of any research regarding Marine Ich and fish survival that studied population reduction and fish survival. Question being….what level of Ich can otherwise healthy fish survive with continual exposure? If UV reduces the Ich population by 50% and ozone contributes another 10% on top of that…is a 60% reduction of Ich organisms in the system worthwhile?

One interesting aspect to me is the debate about whether UV eliminates Ich vs reducing it and improving fish health/survivability. These same reefers, debating UV, will invest heavily in time and financial resources to get 10% faster growth and that last 10% in color from their corals.

 

[allenk4]

In addition to that, talking specifically about Cryptocaryon theronts, these emerge from the resting tomonts in the early morning, while the fish are sleeping. These can rapidly attach to the fish, only inches away from them, and never get anywhere near the intake for a UV sterilizer.....

That makes sense too. Seems we have to fight the Ich Battle at all phases, but maybe as some have suggested, the battle has multiple fronts…starting with building a moat around the reef system with effective QT best practices and continuing the fight by maintaining excellent fish diet and system stability?

 

[allenk4]

Just to clarify - Cryptocaryon CAN be eliminated from marine aquariums through proper quarantine. We tested our main tropical marine system at the Toledo Zoo, where ALL fish entering it (except some sharks and rays) were quarantined with copper/prazi or hyposalinity. We ran eDNA testing, and after a decade of thousands of fish additions, there is no presence of Cryptocaryon. That takes a lot of work though.

If you are talking about my thread on "ich management", in that I say that I developed that thread, not because it works well, but because the pressure from home aquarists is so great to try to manage it because they feel that treatments take too much work (grin).

https://www.reef2reef.com/threads/ich-management.1028274/

Thank you Jay.

‘Ich Always Happens’ seems to me the equivalent of ‘Some Corals just Die’.

Thank you for all your contributions.