UV sterilizer flow rate and viruses

[Spare time]

So I typically see two flow categories, one for protozoa and one for algae+bacteria. Would it be correct to lump viruses into the algae and bacteria flow category?

 

[Zionas]

Following.

 

[h2so4hurts]

Most viruses have a hard candy shell protecting their nucleic acid (nucleoprotein). So many of those will require as high of a dose as the protozoans.

 

[Zionas]

Is it a good idea to leave the UV on 24/7? My LFS thinks no more than 2 hours a day because then too much beneficial bacteria will be killed off, but from my research most of the good bacteria is in the live rock.

 

[TvanB1]

Is it a good idea to leave the UV on 24/7? My LFS thinks no more than 2 hours a day because then too much beneficial bacteria will be killed off, but from my research most of the good bacteria is in the live rock.

I run my 80 watt unit on my 170 gal (total volume) system 24/7. No noticeable negative effects other than a decrease in microfauna population.

 

[Spare time]

The b

Is it a good idea to leave the UV on 24/7? My LFS thinks no more than 2 hours a day because then too much beneficial bacteria will be killed off, but from my research most of the good bacteria is in the live rock.

Depends on the bacteria but nitrifyiers only live on surfaces.

 

[Zionas]

I won’t be stocking any sand sifters, my only goby will be a shrimp goby and its Tiger Pistol companion. Will the depletion in microfauna be a problem?

Will it make my snails starve?

 

[piranhaman00]

If you are using a UV it must be run 24/7 or it is pointless. Unless you are running it solely for clarifying I guess that does not apply.

 

[Spare time]

Depeletion of

I won’t be stocking any sand sifters, my only goby will be a shrimp goby and its Tiger Pistol companion. Will the depletion in microfauna be a problem?

Will it make my snails starve?

No you will be fine. It only kills water column microbes and plankton. This only becomes a bigger issue if you have a lot of non photosynthetic corals or inverts that filter feed on phytoplankton and bacteria.

 

[ReefHog]

So I typically see two flow categories, one for protozoa and one for algae+bacteria. Would it be correct to lump viruses into the algae and bacteria flow category?

 

[Jay Hemdal Verified Community Expert]

Is it a good idea to leave the UV on 24/7? My LFS thinks no more than 2 hours a day because then too much beneficial bacteria will be killed off, but from my research most of the good bacteria is in the live rock.

There is absolutely no basis for only running a UV sterilizer for 2 hours a day. Check any public aquarium, they run them 24/7, change the bulbs at 80% of their rated life, and typically way over-size them. You're correct - the sterilizer can only impact the microorganisms that pass through the tube - so NO bacteria in the LR would ever be affected. That can also, unfortunately be said for any protozoan, virus or bacteria that can live on the host fish and not enter the water column - UV has no benefit controlling those either (sigh).

That all said, back in the late 1970's there used to be a product called Photozone. It was a UV light at a shorter wavelength , and it produced ozone and some other oxidants that carried out into the tank - THAT could sterilize things if used incorrectly.

Jay Hemdal

 

[Jay Hemdal Verified Community Expert]

So I typically see two flow categories, one for protozoa and one for algae+bacteria. Would it be correct to lump viruses into the algae and bacteria flow category?

Darn - I have a copy of Spotte's 1979 Seawater Aquariums at work, but I'm home for a 3 day weekend. I'm fairly certain that book has a good UV dose table in it. However, my recollection is that Spotte uses some weird formula like uw/sec/cm2...I just want GPM and watts (grin). With UV though - when in doubt, more is gooder.....

Jay

 

[proxy001]

dang, some funny comments.
I am a dr and wrote my master thesis on sterilization for non conventional pathogenic agents.( aka PRIONs)

1. Not all virus have envelopes. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462923/). Some enveloped viruses are very weak, some non enveloped virus are very weak...
2. Viruses are usually much easier to inactivate than bacteria or protozoan.
3. pathogenicity is not an all or nothing concept. You need a certain quantity of infective "material" to trigger disease. So using a UV a few hours may reduce the viral/bacterial particle numbers and help "clinically".

That said, given the UV sizes and flow we are using, our UV are not sterilizing water... at all. Sterilizing means eliminating all forms of infectious organisms... If you just decrease that number you are not sterilizing.
I run mine 24/7 , it stops if water temperature gets too high. I am not saying that is the correct way to run UV, just what I do.

 

[fishybizzness]

I run my uv from 6 pm to 6 am. My reasoning for this is twofold. I have always read that cryptocaryon irritans become free swimming and most likely to be affected by the uv during the night to early morning hours. To me, it makes sense to run the uv when its going to be most effective. My second reason is that I don't use any heater or chiller. Running it at night keeps the temps fairly stable when compared to the daytime temperature. I tried running 24-7 for a few days and the temperature kept going above my set shutoff temperature and the uv was constantly turning on and off throughout the day. I don't feel that the constant off and on cycle is good for the uv so I would rather just have it cycle on and off once in a 24 hour period.

 

[Spare time]

The main virus I am interested in would be that which causes cauliflower (lymphocytes) since I do not know of any other way that a system can stop this from spreading.

 

[proxy001]

The main virus I am interested in would be that which causes cauliflower (lymphocytes) since I do not know of any other way that a system can stop this from spreading.

Well, I run UV slow flow and my fish get lympho every once in a while. It goes away after a few days. Not sure if the UV helps or not...

 

[Jay Hemdal Verified Community Expert]

The main virus I am interested in would be that which causes cauliflower (lymphocytes) since I do not know of any other way that a system can stop this from spreading.

Lymphocystis can spread on the fish itself, so UV won't control that. Lymphocystis also spreads when one fish bites infected tissue of another, so again, no control seen. It could help limit spread in a tank, but the reality is, UV sterilization is most effective in plug flow systems, where you are sterilizing water from one tank, and it flows into another (like in fish hatcheries).

Lymphocystis is rarely fatal, and for some unknown reason, it is not nearly as commonly seen as it was back in the 1970s - back then, every royal gramma and emperor angel seemed to contract it!

Jay Hemdal

 

[h2so4hurts]

1. Not all virus have envelopes. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462923/). Some enveloped viruses are very weak, some non enveloped virus are very weak...
2. Viruses are usually much easier to inactivate than bacteria or protozoan.

I'm not going to play the appeal to authority game.

Most all viruses have nucleoprotein called a capsid surrounding their DNA or RNA. Some have envelopes that they steal from a cell's plasma membrane as they bud off and go on to infect other cells. The recommendation for viruses, as posted above, if you want to kill all of them, is the dose recommended for protozoans. But here's a report suggesting as much, for your review: https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.highlight/abstract/1128/report/F. Just because some are easy to kill, doesn't mean all of them are, and you want to default to the worst case scenario, because otherwise, what's the point?

 

[Spare time]

Lymphocystis can spread on the fish itself, so UV won't control that. Lymphocystis also spreads when one fish bites infected tissue of another, so again, no control seen. It could help limit spread in a tank, but the reality is, UV sterilization is most effective in plug flow systems, where you are sterilizing water from one tank, and it flows into another (like in fish hatcheries).

Lymphocystis is rarely fatal, and for some unknown reason, it is not nearly as commonly seen as it was back in the 1970s - back then, every royal gramma and emperor angel seemed to contract it!

Jay Hemdal

Is there a way how It could spread from tank to tank hooked up to one shared system/sump?

 

[proxy001]

I'm not going to play the appeal to authority game.

Most all viruses have nucleoprotein called a capsid surrounding their DNA or RNA. Some have envelopes that they steal from a cell's plasma membrane as they bud off and go on to infect other cells. The recommendation for viruses, as posted above, if you want to kill all of them, is the dose recommended for protozoans. But here's a report suggesting as much, for your review: https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.highlight/abstract/1128/report/F. Just because some are easy to kill, doesn't mean all of them are, and you want to default to the worst case scenario, because otherwise, what's the point?

Right. I remember hearing the argument that UV killed beneficial stuff in the reef tank. What are the latest thoughts on that?