Uv sterilization

Cory · Aug 31, 2020

when water passes through a uv sterilizer, what is it doing to organics? Does it destroy ammonia or nitrate?

MichaelReefer · Aug 31, 2020

Cory said:
when water passes through a uv sterilizer, what is it doing to organics? Does it destroy ammonia or nitrate?

From what I understand, UV only damages/kills Bacteria and Algae.

Cory · Aug 31, 2020

MichaelReefer said:
From what I understand, UV only damages/kills Bacteria and Algae.

It damages dna from what i understood. But im also curious because i read it can destroy urea too.

Ippyroy · Aug 31, 2020

UV only affects living organisms, so no, it will not affect amonia nor nitrates.
For living organisms, it basically destroys there ability to reproduce. Generally speaking it doesn't kill anything, just stops their ability to reproduce.
I don't know what it does to algae.

DSEKULA · Aug 31, 2020

Uv dosent really effect the "organics".you noted, if anything some high amounts of organics may disrupt uv treatment. not necessarily ammonia, but things like random floc in the water could get between the light emited and bacteria or algae shielding it there by lowering uvt. Uv rays sterlize things like bacteria and algae, in very basic terms they are unable to reproduce.

Cory · Aug 31, 2020

Well according to rhf:

"Nitrite can also be broken down by exposure to UV light, producing nitric oxide (NO), hydroxyl radical (OH) and hydroxide ion (OH-)."

"In addition to the standard nitrogen cycle, there are other ways that nitrite can be produced. One of these ways is by photolysis of nitrate. That is, nitrate can break apart when exposed to UV light, producing nitrite and hydroxyl radical (OH)."

http://reefkeeping.com/issues/2005-06/rhf/index.php

HuduVudu · Aug 31, 2020

Cory said:
Well according to rhf:

"Nitrite can also be broken down by exposure to UV light, producing nitric oxide (NO), hydroxyl radical (OH) and hydroxide ion (OH-)."

"In addition to the standard nitrogen cycle, there are other ways that nitrite can be produced. One of these ways is by photolysis of nitrate. That is, nitrate can break apart when exposed to UV light, producing nitrite and hydroxyl radical (OH)."

http://reefkeeping.com/issues/2005-06/rhf/index.php

In a laboratory situation with nitrate-free seawater with no organisms present, ambient sunlight can reduce the nitrite concentration by 2-15% per day.

Sunlight is not equal to the bulb in your sterilizer.

It isn't wise to cherry pick information from articles.

Cory · Aug 31, 2020

HuduVudu said:
Sunlight is not equal to the bulb in your sterilizer.

It isn't wise to cherry pick information from articles.

Is he saying only sunlight does it?

HuduVudu · Aug 31, 2020

Cory said:
Is he saying only sunlight does it?

In the article the parameters are as quoted.

- Laboratory situation
- Nitrate free seawater
- No organisms present
- Ambient sunlight.

If you can reproduce this then you are very likely to see the results as described in the article. Perhaps Randy has furthered this experiment, but you will have to ask him if that is the case otherwise, what he stated in the article is what he tested.

Cory · Sep 1, 2020

Id like to see what @Randy Holmes-Farley has to say

Cory · Sep 2, 2020

Randy Holmes-Farley · Sep 2, 2020

The UV light will be absorbed by many compounds, mostly organics, and that can lead to them undergoing chemical reactions to form new compounds. UV and oxygen together can break down many compounds, and is presumably why many Folks report a reduction in the yellowness of tank water when adding a uv.

Randy Holmes-Farley · Sep 2, 2020

Nitrate can break down under 254 nm light

https://pubs.acs.org/doi/full/10.1021/es002043l

But I do not know how significant those sorts of processes are in a reef tank.

Cory · Sep 2, 2020

Thanks! Ill definitely be able to know once my uv arrives having 150ppm no3 for months now. I got a 90watt in the mail amalgam ho for my 160 gallon.

If my uv is set to high flow and i zap something in it multiple times on a closed loop, will it be like slow flow essentially? For example at 2800gph the uv i got says it does 30,000 uW/cm2, so a particle goes through once and it gets hit by 30,000, but it goes through again in 2 hours, does it get a total 60,000 uw/cm2 dose of uv-c? Or is it repaired in those 2 hours?

ReefBeta · Sep 2, 2020

Wavelengths between about 200 nm and 300 nm are strongly absorbed by nucleic acids. The absorbed energy can result in defects including pyrimidine dimers. These dimers can prevent replication or can prevent the expression of necessary proteins, resulting in the death or inactivation of the organism.

Ultraviolet germicidal irradiation - Wikipedia

en.wikipedia.org

UV kills organism by damaging its DNA. It can also be absorbed by other compound and cause other chemical reaction.

But I don't think it will have much impact of nitrate level. Even if you have enough UV, it's breaking nitrate into nitrite. The nitrogen didn't got taken out of water column. And for nitrite, it will just get converted back to nitrate by nitrite-oxidizing bacteria anyway.

Cory · Sep 3, 2020

Is a uv sterilizer only putting out uv-c or does it also put out uv-a and b?

Randy Holmes-Farley · Sep 3, 2020

Cory said:
Is a uv sterilizer only putting out uv-c or does it also put out uv-a and b?

254 nm primarily, if properly made.

Cory · Sep 3, 2020

Nice thanks! Can anyone answer post 14?

Randy Holmes-Farley · Sep 3, 2020

Cory said:
Thanks! Ill definitely be able to know once my uv arrives having 150ppm no3 for months now. I got a 90watt in the mail amalgam ho for my 160 gallon.

If my uv is set to high flow and i zap something in it multiple times on a closed loop, will it be like slow flow essentially? For example at 2800gph the uv i got says it does 30,000 uW/cm2, so a particle goes through once and it gets hit by 30,000, but it goes through again in 2 hours, does it get a total 60,000 uw/cm2 dose of uv-c? Or is it repaired in those 2 hours?

organisms can do some repair to damaged dna.