# Is it bad to leave U.V. sterilizer running constantly in a planted tank? (why?)



## cgcaver (Jul 10, 2005)

I think I've heard before that this isnt a good idea... can someone tell me why? I was hoping I could run it all the time so I could keep crystal clear water.


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## freshreef (May 14, 2004)

UV wont make crystal clear water , i never use it till there is a problem of gw or something to the fish. 
i dont find it bad idea to use it 24/7 (accepte the uv bulb life) but there is no need for it ...


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## dennis (Mar 1, 2004)

I believe the UV might break down the chelation of many of the traces, making them very hard for the plants to get. I could be wrong though....


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## cgcaver (Jul 10, 2005)

yeh dennis... thats along the lines of stuff I've heard in the past... was just lookin for some facts


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## Raul-7 (Feb 4, 2004)

It has been proven that UV light oxidizes some traces, but most notably Fe (Fe seems to have problems with a lot of things!). But I would recommend you run it after your lights are out. For example, from 12AM to 5AM - that would be a enough to UV the tank a few times and kill any free floating pathogens or algae spores.


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## TWood (Dec 9, 2004)

Where has it been "proven"? 

TW

EDIT: I run my 15W Aqua UV 24/7 on my 90 gallon just as the manufacturer recommends. They said turning it on and off will -shorten- the lamp life. I bought the one with the built-in sleeve wiper - good idea, that. It does make a huge difference in terms of water clarity. It's also great to know that any green dust algae is history once it's been removed from the glass. Green dust spreads far slower now with the UV on all the time. I don't see any evidence of problems with the microtraces caused by the UV.


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## Laith (Sep 4, 2004)

Never owned one...


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## freshreef (May 14, 2004)

Raul-7 said:


> It has been proven that UV light oxidizes some traces.


even if u r right - dosing FE on regular basis would never leave u short with FE even if the UV is working 24/7 - i just dont fint a reason why to let it work in good healthy tank - its like taking medications when u r healthy  
store it and use it only when neccesery


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## Edward (May 25, 2004)

Hi
Running UV 24/7 or not never made any difference in my aquariums and I dose the least amount of trace elements. 

Edward


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## Raul-7 (Feb 4, 2004)

Klaus stated this on APD. I know my words don't mean much, but Klaus a is very respectable person - he helped developed Tropica Master Grow and is an active co-owner(?) at Tropica.

Here's the link: http://fins.actwin.com/aquatic-plants/month.200107/msg00211.html


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## Laith (Sep 4, 2004)

mor b said:


> ... i just dont fint a reason why to let it work in good healthy tank - its like taking medications when u r healthy
> store it and use it only when neccesery


Somehow, this makes a lot of sense to me! [smilie=b: . Having to run a UV 24hrs a day to have clear water is an indication that something is out of balance in the tank...

Sort of like overdosing Excel on a permanent basis to keep BBA at bay, no?


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## plantastic (May 23, 2005)

so many myths abound rgarding UV steralization. Yes, it will break the chelates of some of the more weakly chelated fertilizers; iron is the biggest. However this is not a problem if your dosing regime includes daily additions of iron. Or, if your substrate is rich in iron and the plants that need large amounts of it have a healthy root stock. With the costly price tags of lighting plant tanks, The UV steralizer is the BEST TOOL for assuring maxium water clarity and the most transmission of light to the depths of any aquarium. I would not sell one to somebody under the impression that they need it to be succesful, but I do sell them to people who can afford effective tools/toys!


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## TWood (Dec 9, 2004)

Laith said:


> Having to run a UV 24hrs a day to have clear water is an indication that something is out of balance in the tank...
> 
> Sort of like overdosing Excel on a permanent basis to keep BBA at bay, no?


No. Look through your tank from one end to the other. Remember that. Then run a UV for a week or so. Mentally compare the two. The water will be much clearer after the UV. Was something out of balance before? No. There's just nothing living in the water any more. I can't 'see' the water and the colors of the fish/plants are so much more vibrant because of it.



Raul-7 said:


> Klaus stated this on APD. I know my words don't mean much, but Klaus a is very respectable person - he helped developed Tropica Master Grow and is an active co-owner(?) at Tropica.


As respected as Klaus is, that's still an assertion and not a proof. The UV/chelate issue shows up in some discussions of hydroponics, which is probably where Klaus is coming from. If they are using industrial grade equipment, it may not apply to the hobbyist level stuff.

If you google on variations of UV and chelate, you'll get references to "Stanghellini et al. (1984)" which seems to be the original paper that brought up the chelate issue. Googling that doesn't bring it up. Is there anyone here with access to scholarly articles like that? It would be good to know the conditions of the research in terms of the equipment used and whatnot, and whether it compares properly to hobbyist versions.

TW


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## Cavan Allen (Jul 22, 2004)

Is it always bad to keep a UV running all the time? Not necessarily. Some people seem to get away with it.

Can it be a problem? *YES!* I've seen for myself that having one on can lead to plants that are MUCH paler and smaller, even with elevated micro nutrient dosing.

I really don't know why some people are able to get away with it and I wasn't. But in the long run, I don't think they're really necessary.


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## standoyo (Aug 25, 2005)

hi all,

UV ing is like blanket bombing no? killing almost everything that *passes thru* it no?

pros, good to keep diatoms in check, water clarity improved, harmful pathogens are neutralised...
cons, the good bacteria is destroyed, [arguably] some trace like chelated fe is broken down, high cost of running, fishes and critters have low resistance to when tranferred to less strerile tanks...

boils down to these pros and cons...


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## TWood (Dec 9, 2004)

Cavan Allen said:


> Some people seem to get away with it.


Interesting choice of words, like we're somehow cheating? UV is just another tool in the toolkit that makes the tank look better and easier to manage.



Cavan Allen said:


> Can it be a problem? *YES!* I've seen for myself that having one on can lead to plants that are MUCH paler and smaller, even with elevated micro nutrient dosing.


Unless it was a controlled study, how do you know for certain that there wasn't something else going on at the same time?



Cavan Allen said:


> I really don't know why some people are able to get away with it and I wasn't. But in the long run, I don't think they're really necessary.


Automatic transmissions, power steering, and anti-lock brakes aren't 'necessary' to drive a car, but they make it so much easier and more enjoyable. But XM radio, now that's just silly...

TW


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## Cavan Allen (Jul 22, 2004)

> Interesting choice of words, like we're somehow cheating? UV is just another tool in the toolkit that makes the tank look better and easier to manage.


Ummm.... I meant to say that some people use them with no apparent ill effects. Not that you're "cheating" or anything. If it works for you, good, but I hardly think it's the most important thing for someone's tank and not the first thing that money should be spent on. Feel free to disagree.



> Unless it was a controlled study, how do you know for certain that there wasn't something else going on at the same time?


The white plant growth stopped when I removed the Uv. Nothing else changed. That's good enough for me.


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## niko (Jan 28, 2004)

When we talk about UV sterilizers and if it's ok to use them 24/7 let's not forget that every manufacturer has different claims about the efficiency, optimal flow rate, etc. 

From what we see in the specifications of different sterilizers nobody can say "My sterilizer kills everything that passes through it." Every manufacturer tests their sterilizer at certain flow rates but often we run them at flows that are much higher.

It's a fact though that sterilizers do make the water extra clear. But only if it was clean to start with. A sterilizer will not clear a murky soup and it will not be 100% effective against every single GW occurence you have.

I personally have an 18 watt sterilizer hooked up to one of the filters of my 180 gal tank. The effective flow through the sterilizer is about 110-120 gph because of the height of the tank. I can't say I have noticed any difference running the sterilizer 24/7 or not running it at all. I have never had GW in that tank for 3 years while most of my other tanks have, but that proves little. 

I see the role of the UV sterilizer more as a good preventive than mandatory or harmful to bacteria and detrimental to chelated or other elements.

--Nikolay


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## plantastic (May 23, 2005)

Not all UV steralizers are of the same quality! The turbo twist style (power compact bulb) steralizers are the least effective. The strength of the radiated light will rupture single celled organisms (green water), but does not radiate stong enough to rupture the nucleus of the cell. What this means is that it will eradicate a green water algae bloom, but it will not make the water CRYSTAL clear.

The Emperor Aquatics and Aqua Ultraviolet units are the most effective. They will not only rupture the nucleus of green water algae cells, but also radiate strong enough to be effective against multi-celled organisms, ie. parasites, and bacteria blooms. These types of units use t-5 bulbs.

UV steralizers are not effective against BENEFICIAL bacteria. These bacteria do not live in the water column. The nitrifying (beneficial) and denitrifying (beneficial) bacterias live and reproduce attached to surfaces. These bacterias never pass through the unit. 

UV steralizers show maxium effectiveness when they have their own dedicated pump or power head to run them and has a flow rate that is sized according to the manufacturers recommendations and can turn the tank volume over at the very least once an hour.

Having a UV steralizer in line with any kind of mechanical filter will vary their effectiveness due to the varied flow inherent with clean versus clogged filters.

I have run them on many tanks for many years and they always make a huge difference in water clarity and fish health.

Also they due not reduce the immunity of fish. The number one component of fish health will be diet. The second would be environment, ie. wether or not they are subjected to chronic stress.

Hope this helps some.


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## standoyo (Aug 25, 2005)

_plantastic:Not all UV steralizers are of the same quality!_
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agree with this.

_UV steralizers are not effective against BENEFICIAL bacteria. These bacteria do not live in the water column. The nitrifying (beneficial) and denitrifying (beneficial) bacterias live and reproduce attached to surfaces. These bacterias never pass through the unit._
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don't agree totally with this.
How does bacteria colonise filter in first place?
UVS will increase cycling time of tank. bacteria bloom will be destroyed by dedicated p.head+UVS.
agree that it will not affect beneficial bacteria already in filter. how it gets there if it's not in water? please explain.
beneficial bacteria is all around tank. not just in filter. sticks to leaves, side of tank, gravel etc and multiply and float off to colonise whole tank. your explanation is imo is incorrect.
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_I have run them on many tanks for many years and they always make a huge difference in water clarity and fish health._
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good for you...

_Also they due not reduce the immunity of fish._ 
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for this i think i will have to re-explain and disagree...
organisms living in sterile conditions are defenceless against new/mutated strains of bacteria/virus...it doesn't mean their immune system is weak but it can't recognise new bugs to destroy.
for instance, you introduce a new plant/organism in there that are tainted with lethal foreign bugs and it's goodbye fishy fishy...
like foreigners with flu which they are resistant to but kills natives who run can bear cold with little or no gear on.
Same reason I don't buy fish from farms that use UV...looks great in their tanks but bring home and bye bye...
IMO you are lucky enough not to encounter wipeout. in tropics anything and everything grows...virulent strains of virus and bacteria are common.

The idea of getting clearer water thru a device is appealing and if you can afford is perfectly alright. turning in 24/7 is great if you can afford but is it really necessary? 
IMHO, no. [imagine creating a superbug resistant to UVS?]
IMHO, the tougher the conditions, the tougher the survivors...

hope this helps clears some...

my 2 cents.


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## mstolpner (May 11, 2005)

Just a thought. Don't all the living organisms (including plants and fish) need some "healthy" amount of "bad guys" to stay in their full strength? I think that by providing them sterile environment we will weaken them.


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## Little (Oct 18, 2005)

My contribution to this thread:
An interesting picture on O. Knott's site: http://www.pbase.com/plantella/image/35433515

I don't know if Amano does uses the UV system 24/7. However, the UV sterilizers is not recommanded to be used with Penac Stuffs that Amano uses(Penac P, W or even Penackat), if we follow Plocher's advices...


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## Raul-7 (Feb 4, 2004)

It could be possible for certain bacteria and viruses to become immune to UV light by developing some mutation. The chances are slim, but it can definately happen.


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## Little (Oct 18, 2005)

Raul-7 said:


> It could be possible for certain bacteria and viruses to become immune to UV light by developing some mutation. The chances are slim, but it can definately happen.


There are Bacterias which are naturally resistant to UV sterilizator, and dessication: Deinococcus radiodurans is the name of the bacteria.
I don't know if that type of bacteria would be active in a planted tank, or even could live in it.


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## plantastic (May 23, 2005)

Standoyo-

The UV sterilizer does not create "sterile" water. All of the water does not pass through the unit perfectly like a computer program. Some of the water will go through multiple times and some of the water will miss a few times. The UV sterilizer is used to create the kind of disease and algae organism ratios that are more like what is in nature, as opposed to the unnatural conditions of our closed recirculating tanks.

As for increased cycling time....I have always started CO2 the first day and planted heavily. There is no cycling. If I don't put fish in within the first week, then the plants start crapping out due to no ammonia. I don't even want the bacteria in my tank taking away my precious ammonia! This is because most plants prefer ammonia to nitrite or nitrate. But, as we all know there will eventually be bacteria that colonize all livable surfaces.

Just my experience


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## standoyo (Aug 25, 2005)

plantastic said:


> Standoyo-
> 
> The UV sterilizer does not create "sterile" water. All of the water does not pass through the unit perfectly like a computer program. Some of the water will go through multiple times and some of the water will miss a few times. The UV sterilizer is used to create the kind of disease and algae organism ratios that are more like what is in nature, as opposed to the unnatural conditions of our closed recirculating tanks.
> 
> ...


i find that very interesting that you do without cycling as i do opposite.
maybe because i like the fish more than the plants. they can beg for food. haha...
ok so i'm in planted forum. oops...:-#

it's ok because we all try to speak from experience and try to get better understanding of everybody's preference...as the thread suggests, it's up to reader to digest everybody's personal preference...

funny thing is i have never gotten green water except for tank outside in porch. so UVS is good to use before taking picture for contest? ha! using it 24/7 sounds like luxury if you ignore the seemingly negligible cons of creating superbug.

anyway, UVS is low on my list though it would be like fine tool for some instance of outbreak. pathogenic or algae. or prevention as some say...
thanks for sharing...


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