# UV Sterilizer in a Planted Tank?



## MrsH (Feb 22, 2009)

I have heard / read that a UV Sterilizer (although it may help control algae) is not the best for a planted tank as it may "sterilize" trace elements and prevent plants from reaching their full growth potential.

Comments / feedback?!? Thank you!


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## Shad0w (Nov 13, 2006)

I also heard the same, UV light oxidize trace element, Not sure how true it is. Maybe just a myth.


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## Veloth (Jun 25, 2008)

I thought that UV would just kill living things. I've never seen proof of anything else.


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## rjfurbank (Jan 21, 2008)

I have been using one on my 90g planted tank for >1 yr w/ no noticeable effect on the plants. I think a lot of people use them w/ no ill effects from what I have read here.

-Roy


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## Newt (Apr 1, 2004)

UV light, I believe, only affects organics.


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## vancat (Nov 5, 2004)

Lots of people here use them.


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## MrsH (Feb 22, 2009)

Thank you so much for all the feedback - very helpful.


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## Cavan Allen (Jul 22, 2004)

Some people seem to get away with it, but your mileage may vary. I had one on a 30 gallon a few years back and no matter how much iron I added, many of the plants looked pale and sickly. I suppose you could get around that with root fertilizing if it became a problem, but to me, a UV is good to have on hand for special circumstances (green water, disease, etc) but nothing more.


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## Tex Gal (Nov 1, 2007)

I use a UV 24/7. My plants grow like crazy. I don't have to worry about fish diseases. I think it's great.


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## Shad0w (Nov 13, 2006)

Cavan Allen said:


> Some people seem to get away with it, but your mileage may vary. I had one on a 30 gallon a few years back and no matter how much iron I added, many of the plants looked pale and sickly. I suppose you could get around that with root fertilizing if it became a problem, but to me, a UV is good to have on hand for special circumstances (green water, disease, etc) but nothing more.


have you try disconnect the UV and compare the plant progress?


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## TAB (Feb 7, 2009)

just remember average life of a bulbe is 8000 hours. thats only 11 months... so you must change the blubs atleast once a year. Also if you don't have the correct dwell time, your just throwing money away.


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## Cavan Allen (Jul 22, 2004)

I did, and they looked much better. I've seen other tanks that had them running, and while it wasn't as bad as in my tank, I could still tell a UV was running. In a well-run tank, they just aren't necessary. I'd save money for something else.


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## ray-the-pilot (May 14, 2008)

Cavan Allen said:


> I did, and they looked much better. I've seen other tanks that had them running, and while it wasn't as bad as in my tank, I could still tell a UV was running. In a well-run tank, they just aren't necessary. I'd save money for something else.


How can you tell a UV is running in a tank? I run mine 24/7 so the only difference I see is "No green water." Are you saying that the way you can tell if a tank has a UV sterilizer is by how green the water is?


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## davemonkey (Mar 29, 2008)

ray-the-pilot said:


> How can you tell a UV is running in a tank? I run mine 24/7 so the only difference I see is "No green water." Are you saying that the way you can tell if a tank has a UV sterilizer is by how green the water is?


I think he was referring to the plants looking defficient in iron or other micronutrients.


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## Newt (Apr 1, 2004)

I unplugged mine today to see if there is a difference.
Stay Tuned.:fencing:


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## ray-the-pilot (May 14, 2008)

Newt said:


> I unplugged mine today to see if there is a difference.
> Stay Tuned.:fencing:


Are you serious?

What do you expect to see?


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## Newt (Apr 1, 2004)

ray-the-pilot said:


> Are you serious?
> 
> What do you expect to see?


I have no idea what to expect if anything at all.
I do know that a UV sterilizer will affect chelates (D. Walstad) and possibly F. Excel.
I also know that I do not have green water nor fish diseases.


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## Cavan Allen (Jul 22, 2004)

davemonkey said:


> I think he was referring to the plants looking defficient in iron or other micronutrients.


Exactly. It's a combination of plants that look a bit washed out and starkly clear water.


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## mountaindew (Jul 22, 2007)

IMHO I would not own an aquarium without uv! They are a good piece of equipment for adding more control of the water column in larger aquariums. And having multiple tanks with a couple hundered gallons of water to manage, I look for any little thing to help me!
my 2 cents worth
-md


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## wkndracer (Mar 23, 2008)

Newt said:


> I have no idea what to expect if anything at all.
> I do know that a UV sterilizer will affect chelates (D. Walstad) and possibly F. Excel.
> I also know that I do not have green water nor fish diseases.


UV use does break down excel as the chemical components are photo chemically reactive that's a confirmed fact. Chelated Fe is another matter. No disrespect to Ms. Walstad (as you quoted her) but there are several different chelating agents commonly used. What one is effected by may not affect another. High O2 levels accelerate Fe conversion but the UV link has not been verified. To quote another respected authority on planted tanks T. Barr advocates UV use but on a cycled basis. UV sterilization has documented benefit in its use and should not be dismissed.


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## MrsH (Feb 22, 2009)

wkndracer said:


> T. Barr advocates UV use but on a cycled basis. UV sterilization has documented benefit in its use and should not be dismissed.


Do you have info on the recommended cycle??


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## Newt (Apr 1, 2004)

I opened a thread in the Seachem forum and posed the question of UV light on their products.
See the answer here on this link: http://www.aquaticplantcentral.com/forumapc/seachem/62573-uv-light-planted-tank.html#post474228

They do not use EDTA as a chelant which is the one D.Walstad said would be affected.


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## ray-the-pilot (May 14, 2008)

My research would indicate that Iron goes away in 24 hours UV or not. It precipitates out as Fe(OH)3 rather quickly. 

I believe that precipitated Fe salts can be adsorbed by rooted plants; so, even if you have 0 ppm Fe in your water column you can still have a lot of Fe in you tank. 

I fertilize using PPS pro and I change 20% of my water each week. I can say for a fact that most of the Fe winds up in the filter or substrate. (I’ve checked the substrate and filter media for iron). Despite this my plants grow annoyingly too fast. 

I honestly can say that I do not know what a deficiency is using PPS pro. 

My experience is that 24/7 UV will not result in any deficiencies if you are on PPS pro.


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