# To UV sterilize or not, + or -



## MPKS92 (Nov 5, 2010)

Just been seeing alot of UV sterilizers latly. Is there a a benefit, if so what is it, and what are the negatives. Speaking in terms with a cichlid freshwater tank Thanks PKS92


----------



## fmueller (Jan 11, 2004)

The purpose of UV sterilizers is to kill a organisms that are suspended in the water and go through the filter. The main targets are bacteria and algae. The latter is mostly a problem in ponds where you can get green water in summer. Supposedly it works like a charm, but I've never heard about that being much of an issue in tanks. Regarding bacteria, with healthy fish in an established tank, there should be no need to kill them. In fact, you might nuke some beneficial bacteria in the process, but the nitrifying bacteria that are responsible for the nitrogen cycle live on surfaces, and would not usually flow through a UV filter.

The main downside of UV sterilizers is cost. They aren't cheap to buy, they use quite a bit of energy, and they need regular bulb replacements. The latter is probably the main issue since bulbs can be expensive.

Running a UV sterilizer permanently on a cichlid tank (all cichlids are freshwater) in my experience is not worth the expense. For some time I have been toying with the idea of buying a portable UV sterilizer that I could hang on a tank in case of a disease outbreak or other problems. So far I haven't had the need, and I haven't followed through on it. Maybe one day I'll find a cheap used UV sterilizer


----------



## Pali (Dec 22, 2009)

I have a 7 watt UV filter, so energy cost don't have to be a huge issue.

They do work as mentioned against, bacteria and free floating green algea (green water)

My 7 watt UV filter have been in use a few times, Im able to treat 170 gal water turning it from green pea soup back into clear water in 10 days. It's the biggest water volume I have had it hooked up to, so can't say if it can do bigger volumes. 170 gal im shure it can handle!

So I would say the main PITA is to buy the filter, once you have it there is very little amount of money out the pocket. Replaceing the bulp is costly, so don't drop it. The lifespand on the bulp is around 9-10000 hours, so if it run 24/7 you need to replace it once a year. I payed aprox 100 $ for the filter incl bulp, so compared to doing daily water changes untill the green water is gone, it's not a bad deal IMO.

I only run the bulp if needed, also possible to move the filter from one tank to another if another tank should turn green.

If it's bad bacteria infection in the tank, I would isolate the fish and sterilize the tank, filter and everything else in a more effective way then UV treatment of the water. There I would treat the tank, filter and everything and then reestablish a good bacteria culture.

I have not seen any negative sides in useing UV filters, IMO both the 100 $ and the cost of running a 7 watt bulp for 2 weeks. Seems like a cheap and pretty sweet deal, compared to I was'nt able to see my 1200 $ woth of fish in the tank.


----------



## zoyvig (Oct 27, 2006)

I moved this past year into a much smaller home and kept only a single 90 gal aquarium which I had to place on a heavily lighted porch; therefore I experienced extreme algae.

I asked for help on this forum and an uv sterilizer was recommended. I purchased a 13w submersible unit for approx $40 (with shipping) on ebay and have run it on a timer for 8 hr/day as was suggested on the forum.

Amazing is the best way to describe the results!


----------



## MPKS92 (Nov 5, 2010)

thanx for the info, sounds like only logical use would be for a hospital tank or if your tank had algee or a bad bacterial infection of sorts.


----------

