# UW sterilization, how long?



## john.shephard26 (Mar 8, 2011)

Hi, I just bought a SUN SUN canister and I was wondering how long should I keep my UW light sterilization a day?


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## Yo-han (Oct 15, 2010)

It depends, when you only use a rich substrate you can keep it on 24/7, the only reason not to keep it on 24/7 is it breaks down the chelators of liquid tracemix/iron.
In case you use that you can run it for 24 hour after you waterchange and then add traces. Or only run it in case of trouble (green water, new fish or something).


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## neilshieh (Jun 24, 2010)

i would recommend against running it 24/7. run it occasionally, perhaps after water changes for a couple of hours? the uv sterilization will actually weaken the plastic housing especially since it's a filter from china... don't get me wrong it's a great filter but be wary of the construction. 
you can run it when you have green water or ick as well.


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## DonaldmBoyer (Aug 18, 2005)

Well, just to be a total oddball and confuse you, I run mine 24-7. I've never had a problem with it always being on.


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## Diana K (Dec 20, 2007)

I would just run it when there are problems, and the duration will be based on the problem. 
Green water algae may be taken care of in just a couple of days. Ich will probably need a couple of weeks to be sure it is all dead and not going to come back.


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## DonaldmBoyer (Aug 18, 2005)

Diana indirectly makes the point as to why I leave mine sterilizer on all the time: ich and algae are always present in a tank. It's a safeguard......a nicely mature system with healthy fish shouldn't "need" a UV sterilizer running at all. However, I enjoy having the peace of mind.


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## john.shephard26 (Mar 8, 2011)

Actually I don't have any problems with ich or green algae I just bought a canister with UW light and I was wondering how to use it.
BTW, this is very important, HOW CAN I CHECK IF THE BULB IS EFFECTIVE? 
What I mean is that these bulbs like all others have a certain period that are effective so is there some kind of test (preferably DIY kind) that I could verify that my bulb is in working order?


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## houseofcards (Feb 16, 2005)

DonaldmBoyer said:


> Diana indirectly makes the point as to why I leave mine sterilizer on all the time: ich and algae are always present in a tank. It's a safeguard......a nicely mature system with healthy fish shouldn't "need" a UV sterilizer running at all. However, I enjoy having the peace of mind.


Set it and forget it. I've run 24/7 also for well over three years on several tanks with no issues. The plants all did great no deficiences. There are only benefits to running 24/7. It's true many tanks don't need it, but I've noticed a larger increase in the acclimation success of cardinal tetras for example. Since stress weakens the immune system many fish succumb to parasites in the water. If the flow is correct the UV will make the water 'cleaner' and the fish are less likely to get infected.


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## DonaldmBoyer (Aug 18, 2005)

Ich and algae are always present in a tank; obviously, you have a nicely mature system with healthy inhabitants, so you wouldn't observe algae or ich problems. It doesn't mean that they both aren't present in the system. UV sterilizers aren't "required" to keep algae amounts low or ich in-check, but they are nice to have operating on a "just in case" basis. UV bulbs are generally good for about a year, and as far as I know, the only DIY ways to test their effectiveness is to see if you either start getting algae issues though you haven't changed any of your other variables (ferts, lighting, photoperiod, etc), or if you could take a sample of the water coming out of the outflow and determine the amount of living to dead microorganisms vs. "regular" tank water over a period of time. When the amount of living microorganisms starts to rapidly increase in the tank water and the water sample from the outflow from the canister, then the UV bulb likely needs to be changed. This assumes you have access to a microscope, which most people don't. It is simply just much easier to follow the manufacturer's recommendations and change the UV bulb according to their schedule, usually about every year.


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## john.shephard26 (Mar 8, 2011)

I have green spot algae from lack of Phosphorus (I've increased dosage of KH2PO4) and I know that here UW lamp shouldn't even help but I also have something like dust algae(green brownish color) on the glass which I regularly wipe but keeps coming back.Could this be indicator that the lamp is bad?
BTW my canisters flow is quite slow which only helps the effect of UW.


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## whispyb (Nov 12, 2012)

I run mine 24/7 and have never had any problems.


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