Will UV sterilizers kill both good and bad bacteria?

[Kalinkacat]

I was thinking of installing a UV sterilizer but started questioning that if it kills bacteria, it would make sense that it would kill the good bacteria grown during cycling as well.  So does that mean it would basically harm the tank?
Thanks.

[Mike L]

Proper nitrogen cycle management and regular water changes are far more effective in the maintenance of your tanks. Imo the uv sterilizer is more a backup. The cost of bulbs and unit have to be weighed vs the above mentioned efforts which we should be doing anyway.
Mike

[charlie]

The way I think about it, is that there very little effect on the bacteria as most of the colony is on the various surfaces and not free floating.  I may be wrong, but I have not observed any negative issues with the two  I run.
Regards

[bergenm]

UV sterilizers only affect what flows through them (free floating viruses, parasites, bacteria, & algae). Good bacteria in the filter and on the gravel will not be impacted. Likewise viruses, bacteria, and parasites on fish will not be removed.

[Mike L]

Why do people run them. I'm assuming in the case of planted it has to do with the potential for bacteria  affecting plants?

[exv152]

As a preventative, UV greatly helps destroy micro organisms & pathogens that lead to disease, not to mention helps reduce green free floating algae. I've been running them for years and strongly believe they have had a positive effect on my fish's health. It's hard to quantify/measure a preventative, and it doesn't replace regular water changes and other regular maintenance.

[bergenm]

I'm more of a pond guy...

I have used them to control free-floating single-cell algae when the balance in the pond is off. I believe this is the same reason they use them in the planted tanks - lots of light and lots of ferts has the potential for lots of algae...

I will also use them if I am concerned about a fish either to prevent viruses/bacteria/parasites spreading in the main pond or to run in my hospital tank to reduce the load on a sick fish.

I don't run them all the time, only when needed.

[Mike L]

Thanks for the info people. It was a learning question only. Again thanks.

[Kalinkacat]

Thanks Everyone,

I think I will put UVs in some of my tanks but I wanted to be sure that I was not going to harm the good bacteria.

Thanks.

[George2]

Why do people run them. I'm assuming in the case of planted it has to do with the potential for bacteria  affecting plants?

I once had a major problem with green water algae in one of my planted aquariums and I tried everything over a 4-5 month period. I was almost ready to give up on that tank when I tried a UV sterilizer. The UV sterilizer completely and permanently eradicated the algae within a week or so.  :)   I monitored my various water parameters while I used the UV sterilizer and did not observe a change in anything.


George

[wolfiewill]

I have a portable UV sterilizer available if you want to try one out to see if there is a gain in your case. I move it from tank to tank as needed and only purchase one for a specific tank if there seems to be a need. I have two tanks that have permanent sterilizers, and the rest either haven't shown a need, or have benefited from a couple of weeks with one but haven't needed a repeat treatment. My opinion is that not all tanks need them. I've got 6 fully planted tanks that have never needed one. And it works really well on green water - a few days is all that's needed. Here's a good reference site for this topic:

http://www.americanaquariumproducts.com/AquariumUVSterilization.html