T5 & Uv & Cyano Warning !

[foztek]

I would like to share an important information with you;

We were observeing cyanobacteria first starts on the left and right sides of
the tanks; We found that, many aquariums facing cyano problems has the
same issue.

Our first thoughts about this problem is that it may have a relationship with
the t5 lightings. We observe that when t5 tubes become old, light density and
power first starts to decline on the each side of the tube near sockets.

"Fluorescent lamps are tubular glass envelopes containing argon (or krypton),
a small amount of mercury and selected phosphors. Supplying adequate
current to electrodes at the ends of the tube generates an electrical arc
resulting in production of invisible ultraviolet (UV) energy, which excites, and
is absorbed by, the phosphors. These phosphors then emit (fluoresce) the
absorbed UV energy as visible light." (www.advancedaquarist.com)


According to this information, phosphorus is the main element that converts
UV to visible light. Mixtures of phosphors within fluorescent lamps produce
various light qualities and colours.

Now we know that when the t5 tubes become old, phosphors in tubes start to
loose its effect. If phosphors loose its power to absorb UV, what will set free
during this time? :spin2:

The answer is UV. :thumbsup:

Phosphors first start to loose its effect on the each side of the t5 tubes, if
you look at your old tubes, you will find that you lamp has dark sections on
the each side of the tube. So these both ends starts to emit UV to your
aquarium.

According to our research; this UV light kills micro-fauna in aquariums and
under these circumstances Cyanobacteria have an opportunity to grow
because of its resistance to UV light. We will explain later why Cyanobacteria
has resistance to UV.

P.S : All these information is based on our observations and tests. Some of
these informations has no scientific measure.

This new thread is posted to argue about this subject and have your opinions
as well.

Cihan Toprak & Firat Oztek

 

[karaadam]

Here are some pictures about cyanobacteria formation on the sides only

 

[A. cervicornis]

That's really interesting, thanks for sharing this. I've noticed this tendency in some aquariums in the past, but I was always able to attribute it to the flow patterns in those aquariums. This should start an interesting discussion. I'm sure everyone on this message board would be interested to hear more about your research- are you running experiments to test the theory?

 

[Dadekster]

I am sure its a bit different for each bulb, but could you narrow down what you mean when you say 'old'? We talking 2 months old, six, year or 2 years?

 

[digitalchrisg]

Indeed interesting observations... I always try to cycle my tubes out on a schedual regardless of if they are still working to avoid this type of trouble, but very interesting to think it may start from the sides like that.

 

[Nano sapiens]

Interesting, hadn't really attributed the Cyano increase to increased UV, but more along the lines of spectrum shift.

Would be interesting to analyze the spectrum of an older T5 along different parts of the tube to see how much variance occurs.

 

[digitalchrisg]

Interesting, hadn't really attributed the Cyano increase to increased UV, but more along the lines of spectrum shift.

I guess a spectrum shift could be just any shift in color. But isn't that what is going on if they are going to uv? I mean what I had assumed was that the bulbs where shifting more into the uv range right?

I guess it would be interesting to see exactly what type of light the bulbs are putting out at that stage. The thing I found most interesting about this whole thing was that he feels that the bulbs burn out from the ends in rather than uniformly. I guess it makes sense, but I would have never thought of that.

 

[Nano sapiens]

When I mentioned spectrum shift I was thinking more in terms of the shift within the spectrum visible to our naked eye, but you are correct that UV, IR, X-ray, Gamma Ray, etc. are all technically included. I hadn't thought about a shift from the high end of the visible spectum into the UV as a positive for Cyano, but it is an interesting idea.

 

[wtac]

The blackening of the ends isn't the loss of phosphor coating but the deposition of mercury. The darkening is more prevalent at the ends as that is where the electrodes are to "excite" the mercury gas into UV emission. From what I remember in my spectrometry classes, the deposition is from the "sputtering effect". You will see the darkening in the glass envelopes in MH/HQI bulbs from the sputtering.

The addition of argon or any of the noble gases is to prevent the electrodes from burning out, like the incandescent light bulb. If anyone has seen FL bulbs (non aquarium related) that takes longer to light up, or just not light up but you see the ends glow, or even side by side comparison of new FL tubes vs older tubes, the former being brighter, it's from the loss of mercury, not the loss of phosphors.

 

[billsreef]

The typical spectrum shift of flourescent tubes due to age is to shift towards the red end of the spectrum, not towards the UV . In fact, daylight tubes being used on reptiles for the sake of the UV they emit need to be replaced due the fact they shift away from the UV spectrum.

Also the germicidal UV wavelengths that would kill off things does not penetrate through water very far, certainly not far enough to enhance cyano growth. However, the shift away from the blue side towards the red side of the spectrum does impede the growth of more desirable algaes that might be outcompeting the cyano for space, hence the cyano bloom when the spectrum shift allows it to outcompete the good stuff.

 

[Hydrologist]

I have noticed the cyano growth starting on the sides of most tanks as well, however I have attributed that growth to lack of flow along the edges of these tanks as there PH/flow were all facing the middle of there tanks leaving substantial dead spots along the sides of the aquariums.

 

[Frank Aguirre]

I have a 300 gal tank with this problem

I have a 300 gal tank with this problem

This tank receives the light of 12 T5 bulbs at 54 watts each.

While coral growth has been so so Coralline algae has been growing really fast.

My thoughts were about skimming capacity and not lighting related. I have an Ocean Motions device for close loop and Blue line 100 pump bringing plenty of water back from the sump.

I do water change and the red slime disappears for a week or so I skip on my weekly water change and it comes back with fury. Making mats of rd slime at the center of the tank

 

[Muddy35]

Personally~ I have been running LEDs (CREEs) for a month now and a 400w MH 10K ushio for 4 months prior to that. THIS tank has been skimmerless for the 7 months its been setup. I have a spot about 3x3"s with cyano. This is located in a spot that recieves very little light and LOW flow. PO4 and nitates are undetectable. based off the assumption the cyano is caused by UV I would have to disagree based off the color spectrums of the LEDs I am using and the spectrum sheets/data from cree.

IME~ and looking at the pics posted above LOW flow gives cyano a foothold and pace to grow. As with past tanks and current tank- increasing flow will not allow it to take hold and spread as what your seeing. Vacumn what you see and add powerheads that wil move a swift amount of water across the bottom of the tank but not swift enough to blow your sand everywhere (yes you will have sand movement until it all settles into its placed based on flow) ..

Personally I dont think lighting spectrum has alot to do with it. I wont go into this discussion here as its very lengthy.. But I do believe any spectrum that will grow coral or algea will also grow cyano.

Just my 2cents worth and certainly not based off any scientific observations..

 

[Hookup]

If I understood the OP, the theory is that UV doesn't benefit cyano directly, but is a detriment to competing bacterias/algae/organisms and creates an easier environment for Cyano to get a hold and take-off.

The first thing that jumped into my mind was that there would have to be some definitive measure, at depth, of the UV being produced. My second thought was, if this is true, why did I just by a UV Sterilizer?

Though I like the theory and the linkages, I think it something that requires further empirical study before any conclusion could be drawn. Great theory, looking forward to more study results.

 

[karaadam]

We do not mean the UV is the only basis for cyano.
There are several reasons for cyanos.

1 - Drastic change in wavelength (replacement of the tubes).
2 - Biological changes that destroys the micro fauna (Heat, salinity, new bacteria, etc.)
3 - Chemical modifications that destroys the micro fauna . (Kh, ph, silicate,po4, etc)
4 - Bad quality T5 tubes or outdated tubes (UV, wavelengths)

 

[possys]

I been using LED from eco light for about 8ms and have cyano on one life side of my tank. 30G and one MP10 pump.

 

[HerbanShaman]

I don't agree ; lots of other lights e.g Actinic (420 ~350 =UV) produce UV. Thats why corals glow in UV. Its the most efficient means of dissapating excess energy of this spectra (vs foerster transfer or thermal). I also think there are lots of other reasons that cyanobacteria favors the side of the tanks. Flow, competition, etc. They're nitrogen fixers so they thrive in a low nutrient environment, they need no cause lol. People are always looking to blame something for thier cyanobacteria.

 

[chuckreef]

If you are correct Foztek, then you are saying you experimented and replaced these old tubes with brand new ones and the previously UV-impacted microorganisms returned to these areas and the Cyano declined and dissappered.
Is that so? Can you show us your data?

 

[chuckreef]

I dias agree with this part.

Phosphors first start to loose its effect on the each side of the t5 tubes, if
you look at your old tubes, you will find that you lamp has dark sections on
the each side of the tube. So these both ends starts to emit UV to your
aquarium.

The dark areas are caused by the release of sputtered materials from the filaments (which are close to the ends). These sputtered materials coat over the phosphors and prevent the UV from reaching the phosphors (I.e., it shields them). And, as a result, the lamp burns dimmer at the ends. In fact, there would be less UV emitted from the ends of the lamp as a result of age, not more.

 

[karaadam]

Any new observations?