29 replies to this topic

[simmoman]

My poor fish had a bout of itchiness and under advice I gave them a dose of white spot treatment and afterwards installed a UV light filter, (not part of the treatment plan).

I know that it kills parasites and green algae but that's all. I've since noticed that the water is cleaner in general and when I used a powerhead to stir up fish muck from hard to get places, there's hardly any to stir up.

Is it my imagination or have others experienced the same thing from using a UV filter or has my water management technique suddenly improve without me knowing.

[sandgroper]

The UV won't magically get rid of waste, it's basically a water sterilizer. It will help to keep the water clearer, very useful for out door ponds with green water. They seem to keep the dreaded white spot disease in check as i couldn't keep clown loaches without them getting white spot. Since putting a 18 watt UV on each cannister i haven't had a problem since and that was 7 years ago. cheers steve

[Anka]

Do they kill any beneficial bacteria or microorganisms?

[sandgroper]

Yes they will sterilize any organisms in the water colum, thats why you connect it to the return pipe on your system to protect your filter media. cheers steve

[simmoman]

I found this on a website

A UV sterilizer will not kill beneficial bacteria such aerobic bacteria, as this bacterium is effective when attached to a surface of high water flow such as the sponge of a sponge filter, not when in the water column. In fact relatively new scientific evidence shows nitrifying bacteria to be sticky and adheres to the surfaces like glue this is why the myth of UV Sterilizers killing beneficial bacteria is just that, a myth

the instruction say to place it on the inlet side of the filter.

http://www.americana...rilization.html

A lot of reading but below are a couple of notes.

UV sterilization will not cure infected fish of bacterial or fungal diseases. A UV can aid in cure by killing bacterial pathogens in the water column and fungal spores, also by improvement of the Redox potential (which is much more important than many realize based on scientific research) and general water quality.

A UV sterilizer will not kill ich trophozoites already on the fish (but then medications don't either), but UVC can again slow the spread of ich tomites in the water column (but usually not out right kill ich tomites). However by water quality improvement (such as Redox Potential) and lowering of pathogenic bacteria, the fish has more natural resistance to fight Marine Cryptocaryon or FW Ich.


redox potential ----- http://www.americana..._Potential.html
Not the easiest to understand

I suppose one could do a complete study on it but all I need to know is dat it helps me fish, dats good heh.

Cheers

Edited by simmoman, 16 December 2011 - 08:54 PM.

[Neakit]

well to be honest a uv sterilizer isn't bias. If anything goes through the light chamber it will die. not just bad or good.

[Anka]

well to be honest a uv sterilizer isn't bias. If anything goes through the light chamber it will die. not just bad or good.

This worries me... I want one because I want to keep a clean, clear and beautiful tank but do not want to sacrifice the health of my fish

[Bowdy]

I had one on the pond canister I had set up on a tank and I thought it was great. Always had that crystal look to the water.
Cheers.

[Anka]

But is it safe to run 24/7? Considering it will kill good bacteria? (sorry I'm a noob)

[dazzabozza]

Hey Anka

Have a re-read of Simmo's reply above re: bacteria. It suggests that the majority of good bacteria stays in contact with things like filter media, rockwork and substrate in much denser populations compared to what's in the water column. So whatever the UV does kills off wont be much of a negative impact to your tank/fish.


Daz

[Anka]

sweet - gonna go into seaview tomorrow and might buy one to fit inline :3

cheers boys

[simmoman]

When it comes to uv I'm a noob as well. That's why I have to copy and paste the paragraph below. Trying to understand everything on uv filters I would need a degree in water chemistry, I don't have one but what I do know is that a uv filter is great to have along with good aquarium maintenance.

A UV sterilizer will not kill beneficial bacteria such aerobic bacteria, as this bacterium is effective when attached to a surface of high water flow such as the sponge of a sponge filter, not when in the water column. In fact relatively new scientific evidence shows nitrifying bacteria to be sticky and adheres to the surfaces like glue this is why the myth of UV Sterilizers killing beneficial bacteria is just that, a myth.

[sandgroper]

But is it safe to run 24/7? Considering it will kill good bacteria? (sorry I'm a noob)

Yes it's safe to run them 24/7. I should point out that my comments were referring to the in line type UV, where the water is drained from the aquarium into the cannister. The water is filtered thru the cannister and then on the way out back to the tank it passes thu the UV, no good guys will be hurt in this process. cheers steve

[dazzabozza]

Some people run their UV's on the output of their canisters, major reason is you get less gunk buildup in the UV unit as the canister has trapped most of the particles through mechanical filtration. Canisters can also be a home for nasty bacteria so killing it off as it leaves the canister makes more sense.

Also when talking about sterilisation 100% kill rate isn't guaranteed. UV wattage and contact time (flow rate) plays a big part.

[Cawdor]

It's worth noting that a UV filter doesn't replace the need for good husbandry practice, such as regular, sufficient water changes. To me, the UV filter is a safety net in terms of disease control and it also keeps the water visually clean due to killing free floating algae.

It doesn't prevent whitespot for example, but it does kill off the free floating stage of the whitespot parasite, thus disrupting the life cycle and aiding in preventing re-infection.
The combination of wattage and flow rate (and to a degree the design) determine the effectiveness. The longer an organism is exposed to UV light, the more likely it is to be killed. This is a case where lower flow rate is actually desirable (to a degree).

[Neakit]

And again simmoman, unfortunately if it passes through the uv filter its either going to be dead or damn near it.
So you can say its a myth or not doesn't change the fact that if its exposed to the light it will be either dead or damn near it.

[bigjohnnofish]

i understand the benefits of using uv....

but a downside of it is fish dont build up their own immune system from fry growing up..... then one someone sells them and they go into other tanks it makes them extremely vulnerable to any pathogens and bacteria etc.... they invariably get sick and die... a lot of serious L-number collectors wont buy from people who they know use uv on their tanks.... me included....

and im very weary buying from shops that depend on them too...... only my opinion and im sure other people may disagree....

[sandgroper]

A UV isn't going to kill every thing, the fish still have a immune system. The UV just aids in the prevention of things getting out of hand, as stated before you still need to do regular maintenance and if you don't things can still get nasty. I personally wouldn't bother with a UV on a lightly stocked tank as regular maintenance is sufficent, however on a large over stocked tank or a multi tank system running on a sump set up, a UV is a useful tool. cheers Steve

[sydad]

It is necessary to understand several things about the UV treatment of water.

Firstly, there is no such thing as a UV steriliser or UV sterilisation. Sterilisation is an absolute process, and the use of the term refers to the destruction of ALL life forms. UV has little effect on yeasts, and none whatsoever on most bacterial spores. Many protists have the ability to recover from non-fatal exposure to UV by utilising internal enzyme systems (this also occurs with heat damage). Ergo the use of the term "sterilisation" is a total misnomer. At best the process within the aquarium can be considered as disinfection, which term defines the killing of vegetative organisms: but as pointed out, even this event is unlikely with many bacteria. The types of UV systems designed for aquaria are far more likely to damage bacterial cells than to kill them, and recovery from such damage is highly likely; so the spread of bacterial diseases may be difficult or impossible to control using UV.

Secondly, it needs to be recognised that there are many reasons why UV may fail to destroy organisms. These include such factors as inadequate dosage (intensity) and/or exposure time. Shadowing by particulate matter will also contribute to failure.It is of course possible to overcome these restrictions, but aquarium systems are simply too underpowered and poorly designed to do so.

Thirdly it is known that UV is most effective on microscopic non-bacterial organisms. Thus algal cells such as those contributing to "green water" are readily destroyed, as they have no protective or damage recovery. This also applies to microscopic organisms such as the trophonts or "swarmer" stages of Ichthyophthirius and Oodiniun. This means that water can be clarified by UV treatment, and the spread of protozoan diseases halted, with reasonable efficacy.

Any suggestion that UV will affect sessile bacteria and other organisms contributing to the elimination of nitrogen and dissolved carbon problems within the aquarium, is of course pure nonsense, as these organisms are present in the water column in insignificant numbers (unless there has been intense disruption and mechanical mixing of substrata: and even this will affect an insignificant proportion of bacteria within a system).

Concerns that ongoing UV treatment may contribute to the loss of immunological stimuli to fishes within aquaria are probably well founded according to some sources, but it appears that such effects are probably transitory.

Some 20 years of playing around with the of UV in single or isolated aquaria convinced me many years ago that it was basically a waste of time, energy and money; and that the use of UV in aquatic systems is probably best relegated to large numbers of aquaria utilising common filtration/flow systems. However I concede that the desire to eliminate potential problems without actually understanding the processes leading to such problems, will always mean that there are those who will pursue the "easy way out" with total disregard to any form of advice or logic. That's the way things work (or more often don"t).

Syd.

[bigjohnnofish]

interesting.... even after all these years things still aren't an exact science.....

i like to refer to using UV on fry as the same as mum using disinfectant everywhere so kids arent exposed to bacteria... hey mum let the kids play in the dirt!!!!