# UV Sterilizers



## catklyst (Jan 26, 2010)

Are they worth it? Do they prevent only algae and bacteria blooms? All feedback would be highly appreciated.


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## houseofcards (Feb 16, 2005)

In short if your not having problems you really don't need a UV. But if you want to play it safe a UV will prevent GW from ever starting and it will also protect your fish against water borne parasites (assuming the flow is within the correct range). Many advanced aquarists use them for both of the reasons I mentioned.


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## flashbang009 (Aug 6, 2009)

I chose to go for the petsmart carried "AA" brand. I was told they were cheaply made and for $45, i wasn't prepared for much of a stunner. However, it has not broken or anything after 4 months of use, and it comes with a detachable powerhead. Works great for halting green water like houseofcards said, and bacterial infections. Worth it if you may have either!


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## armedbiggiet (May 6, 2006)

It is like buying a insurance... you don't have to have it but I would do it if you have some really hard to get or rare fish or plants. Other wise it is really no need.


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## catklyst (Jan 26, 2010)

Do sterilizers prevent parasites as well?


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## flashbang009 (Aug 6, 2009)

bacterial parasites yes


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## StrungOut (Nov 8, 2004)

I've got one for my 17 gallon and it works great. I still get a little bit of algae here and there but I think it kills it off.


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## Diana K (Dec 20, 2007)

UV can kill single celled things, both algae and parasites, including Ich. 
The trick is to get the right flow. 
ALL the water in the tank needs to pass through the sterilizer. If it does not, then the pest will be able to breed in the tank. A heavily planted tank may not have a good water flow pattern, might have some dead spots. 
If the water flows through too fast the pest is not exposed to the UV long enough to die. This varies with what you are killing. 

I use a UV on a quarantine tank. Less plants and decor to interrupt the water flow. Killed some Ich on Cardinal Tetras with no medication, just the UV. 
I have 2. Both at the 'Green Killing Machine' sold at Pet Smart. I use the smaller one on small tanks, the larger one on large tanks.


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## flashbang009 (Aug 6, 2009)

the sterilizer Diana mentioned is the same one i was talking about, thanks for remembering the name haha.


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## Cliff Mayes (Jan 29, 2007)

Be very careful. UV sterilizers are not the ultimate answer to all problems. Listen very carefully to the answers. "Can" does not mean absolutely will. Yes, UV sterilizers if the bug passes by the clean bulb at the correct speed will kill the bug but all of the bugs in a tank may not pass through the Sterilizer or at the correct speed so Algae Spores and various Parasites and bad bugs may survive the UV sterilizer. UV sterilizers help but they are not the ultimate answer. Good to have, yes but again, they are not the ultimate.


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## Diana K (Dec 20, 2007)

Cliff is exactly right. However, nothing is 100% effective, anyway. Whichever solution you decide on for any specific problem, research so you apply the method correctly, and have a back up solution in mind in case the first solution does not work for whatever reason. Often a combination approach is best. 

Another note about UVs: Many fish medicines are light sensitive, and UV will deactivate the medication, too. If ANY research suggests turning off the tank light while using that medicine, then turn off the UV, too.


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## catklyst (Jan 26, 2010)

none of my fish are sick im just worried after reading about worms and such people get in some of their tanks


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## ObiQuiet (Oct 9, 2009)

I had the same questions to-UV-or-not-to-UV (I'm new at this). Here's what I did, after weighing pros and cons.

I got the in-tank Submariner, 5W. This sits inside the tank, and has a built-in pump.

My rationale was:
a) I wanted water movement in the tank, but not the surface aeration.
b) The "insurance" is comforting, since I don't yet trust my abilities. So, it makes me less nervous when a fish flashes from time to time.

Since it's just a 5 watt, I've let the filter clog a bit to reduce the water flow and increase the dwell time. (BTW, In my reading, UV ratings/rankings seem to consider only the one-time hit of UV and don't consider that the aquarium water cycles through it many times per hour, 24 hours per day. As far as I can tell, this should make even a 5 watt bulb overkill for a 40g.)

I was worried about the known effect of UV light removing usable iron from the water column. Ms. Walstad assured my that I'd be able to find a duty cycle that still kept the floating plants in good shape. So, I have the UV on a timer that runs for 2 hours out of every 6. Will adjust as needed.

-ObiQuiet


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## Diana K (Dec 20, 2007)

Water that passes through the UV several times in a day (or even in an hour) is not really going to kill something that needs to be exposed for a long time. Slowing the water flow will do this. The 'bugs' will stay exposed to the light for a longer time all at once. With shorter exposure they might heal in between trips. 

Also, I see an inconsistency in your comments: You are hoping that running it 24/7 will increase the exposure of the pests to the UV, yet your plan is to run it intermittently.


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## ObiQuiet (Oct 9, 2009)

Diana K,

You're right. I wasn't very clear. Maybe this will be a better explanation...



Diana K said:


> Water that passes through the UV several times in a day (or even in an hour) is not really going to kill something that needs to be exposed for a long time.


In my amateur web searching, I didn't find any documentation about the efficacy of multiple passes. All of the info I found was about wattage and one-pass dwell time.



Diana K said:


> Slowing the water flow will do this. The 'bugs' will stay exposed to the light for a longer time all at once.


I've slowed the water flow by letting the filter get dirty. Consumer mis-understanding is the only reason I can think of that the mfgs don't advertise how _slowly_ they can pump the water...



Diana K said:


> With shorter exposure they might heal in between trips.


Right, they might. I have no way of knowing if the 15-20 minutes between trips through the UV is long enough for some of these organisms to heal themselves.



Diana K said:


> Also, I see an inconsistency in your comments: You are hoping that running it 24/7 will increase the exposure of the pests to the UV, yet your plan is to run it intermittently.


Sorry for the confusion -- I meant to point out that none of the info I could find took into account the possibility of 24x7 operation and multiple cycles of the UV in judging how many watts you need or the dwell time.

I am running mine intermittently for these reasons:
a) I don't expect any introduction of new pathogens, so running it all the time seems like overkill. If the water cycles 3x per hour, and 3-5 passes are fatal, then running it long enough so that I get 90% odds of each organism passing the light 10x per day seems ok.
b) The UV does affect the growth of floating plants (hornwort is dropping needles and the duckweed growth has slowed down)

In short, I'm still guessing and trying this stuff out... and making lots of assumptions.

Cheers,
-ObiQuiet


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## bartoli (May 8, 2006)

ObiQuiet said:


> I've slowed the water flow by letting the filter get dirty.


The newer shipment of Submariner includes a flow regulator that you can use to significantly slow down the water flow. If you don't have it, request one by contacting JBJ Lighting at http://jbjlighting.com.



ObiQuiet said:


> b) The UV does affect the growth of floating plants (hornwort is dropping needles and the duckweed growth has slowed down)


That is consistent with my experience.


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## ObiQuiet (Oct 9, 2009)

bartoli said:


> The newer shipment of Submariner includes a flow regulator that you can use to significantly slow down the water flow. If you don't have it, request one by contacting JBJ Lighting at http://jbjlighting.com.


Great, thanks!! That will be quite nice to have.


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## Alexpatrascu (Feb 9, 2010)

I'm planning on getting one on my 50 gal and attach it to my Eheim 2217.....better safe than sorry....


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## barbarossa4122 (Dec 31, 2009)

Hi,

I have 2 9w GKM. A few days ago I noticed that one of the led 's indicator light from one of the sterilizer got much dimmer than the other one. Do you guys have an idea why? I only used them for about 6 weeks 24/7 but now they are on a timer for 15hrs/day. Thank you.


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## flashbang009 (Aug 6, 2009)

might just be a faulty light. They aren't the highest quality hardware. Maybe try unplugging it, and plugging it back in. Other than that i wouldn't worry about it.


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## barbarossa4122 (Dec 31, 2009)

flashbang009 said:


> might just be a faulty light. They aren't the highest quality hardware. Maybe try unplugging it, and plugging it back in. Other than that i wouldn't worry about it.


It works fine now. I think I'll just use them for 10 to 12hrs /day starting today.


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## swhite (Feb 17, 2010)

I did the 24 watt green killing machine. Like $60 instead of $40 for the 9watt? Head 24w was better at controlling bacteria and has more flow i think.

Incredible!

I did not have GW but sometimes abit off be it a bacteria bloom or whatever. After 2 days it was almost crystal clear. 5 and absolutely perfect. Even the glass hardly builds up algae now.

55gal with 2/wpg lighting and well setup flow using powerhead, in tanks UV with built in flow, bubbler placed to add to flow and good filter pickup location.

Bonus of rarely sick fish too. Cant say enough good about it.


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## dirtyted (Mar 5, 2010)

can I use a uv sterilizer during the tanks beginning cycle or will it kill nitrifying bacteria?


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## flashbang009 (Aug 6, 2009)

Yes you should be able to, most of that bacteria lives on surfaces or under the gravel to my knowledge.


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