Does a UV sterilizer kill beneficial bacteria?

[porcelaindoll]

I just bought a 9 watt uv sterilizer. the guy at the LFS said to only run it 4 hours a day or it will kill off all the beneficial bacteria. Is this true? I've never heard of anyone turning it off. Thought it was supposed to be on all the time.

thanks.

[Devilishturtles]

From my understanding, it is supposed to be run all the time, and yes, it kills beneficial bacteria. That's why alot of people don't use them. Did you buy it for a specific purpose? It can help in getting rid of parasites in your water or maybe really nasty algae.

[porcelaindoll]

I have now read it only kills "free floating" bacteria not beneficial bacteria which is not free floating but attached to live rock, decor...etc.

I bought it to prevent any outbreaks of external parasites and was just told it was good to have to keep aquarium healthy.

[OceanMist]

I will be adding a 25w to my 85g soon, currently have an ich outbreak, I also understand they give the water a crystal clear look.

[fishfreek]

If properly configured (note I said Properly) it will KILL any free floating orgnizium that passes thru the unit unless its extremly large (the orginisum).

Many people under size their UV or have the flow rate to fast causing an exposure period to short for a fatial exposure. We have some wonderful articles written about UV in our articles area.

Carbon will give the water its crystal clear look unless your water is clowdy due to a huge amount of bactera or living algae spores.

[OceanMist]

Carbon?, I'm sure I remember reading somewhere it's achieved by UV, how many wpg of UV is reccomended per gallon then?

[fishfreek]

UV calculation is not just wPG but also GPH flow thru the unit. Carbon will remove yellowing coloration of the water making it crystal clear. UV will only help if you have an algae bloom but you will need good bactera bed to deal with the large volumes of dead algae cells.

[melosu58]

I keep mine on 24/7. UV lights are the debate of the ages. IMO they are great for parasites and algea spores. I dont believe they will do anything for making your water clear. I`ve never had algea or ick in my tank since I got mine eight years ago. Is it because of the UV or is it due to the fact I keep an understocked tank and feed every other day and do PWC`s every week. I dont know but I believe that all are contributors including the UV. As FF said check out the articles on UV`s on this website. Good Question