T5 & Uv & Cyano Warning !

[SushiGirl]

I don't disagree that spectrum shift could affect cyano, but I would put water quality first in the list of causes and lighting shift last, especially with so many using LEDs now for lighting (I see this thread was started in 2010) and there still being cyano in tanks that aren't just going through the new tank phase. We've not seen cyano at all as our T5 bulbs age, though we do notice coral reaction to the shift & we replace bulbs as scheduled.

I'd have to blame other things first for cyano. We just went through a bout in 3 different tanks -- a 2 year old tank with T5s but it only happened in the fuge with LED lighting, and two 6 month old tanks with two different types of LED fixtures. It started in the fall (late October/early November) when the water supply lakes turned over as they do every year, even though we run 0 TDS RO/DI water (first thing we checked!). The cyano has now disappeared as the lakes have finished turning over. It disappeared amazingly fast too! This has happened to many reefing folks in this area. We'll definitely be watching in the spring when the lakes turn back over LOL.

In one of our tanks the flow didn't matter, it was even in the direct blast of the powerheads. In the fuge & the other tank, those are much lower flow. As it started, it first appeared in the low flow areas & as it disappeared, it hung on longest in the low flow areas. Flow can help, but once cyano gets a good foothold, flow doesn't much seem to matter, IME.

These are just my recent observations since it's the most current cyano issue we've had. The 2 year old tank went through a small one last fall but we didn't really put it together since we had found 21 TDS in our stored water (we quit storing it in those containers) and it was our only tank. This time we had more tanks and various lighting on each so it was a little easier to realize there was only one common denominator, the water & the salt. Since we're still using the same salt over this period, that left the water.

 

[ReeferBatman]

Some points...


UV has a lot of characteristics going on for it, some UV A light between 300-400nm, is in fact used by some corals... and is present even below 100 ft in the ocean depending on water quality...

So corals have mostly evolved to photo-synthetically take advantage of, or at least limit their own exposure to [reflect] UV A light.

The further 'down' the spectrum you go the more harm is inflicted to biological organisms.

UV-B light is not readily known as a source for photosynthesis.
UV-C light (light 100-290nm) is what really causes the most harm to cells... and that's the light your UV sterilizer would most likely use (I haven't actually looked into those products, don't know for sure...)

Glass filters out the lower wavelengths significantly... why MH have glass filter/covers, etc.

If you have a Glass top over your tank, UV shouldn't really be an issue - especially not the small increase from a T5 fading.

Cyano likes higher registers of light, so UV wouldn't be a supporting factor...

 

[ReeferBatman]

Excess UV light (relative to what the coral evolved with) can actually lead to photo-inhibition...

Which along with less intensity (less of the good light), may be why we attribute 'old bulbs' with slower coral growth... just a thought.

 

[6lilfish]

Thanks for this post I have that same problem

 

[arkoujohn]

Anyone replaced his old T5 tubes with new ones and observed even a small change in cyano?

 

[Ron Reefman]

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.

I know this was an comment made almost 2 years ago. I just saw it. And my understanding is that the blue and shorter wavelength end of the light spectrum, like UV, penetrates the water better than the other colors and they all have virtually no problem getting down 2 feet in an aquarium.

"This applies to aquariums when we consider the light spectrum and how it applies to our aquariums individual needs: Red light is the first to be filtered out and can only penetrate a short distance. As light waves penetrate deeper into the water, orange and yellow are lost next. Of all the colors of the spectrum blue light penetrates the deepest. Corals need intense equatorial UVA (actinic) as well as other aspects of PAR. "

And I'm not saying the OP ideas about light is right or wrong. I think they may have a nugget of validity but there is so much more that plays into the development of cyano bacteria, like carbon for food and water flow along with lighting issues. Personally, I think the OP's idea of the reason cyano starts at the ends of the tank (if than assumption is even correct) is due to water movement, or the lack of it, at the ends of the tank.

 

[Ron Reefman]

Anyone replaced his old T5 tubes with new ones and observed even a small change in cyano?

Tons of people replace 6 month old and 9 month old t5 bulbs and claim it makes all there nuisance algae go away, why not cyano bacteria as well?

BTW, I don't agree with it affecting either algae or cyano to any significant level (just my opinion, I'm no expert). But I understand lots and lots of other people do. I'll agree it being a contributing cause, but far from being the only cause. It's just the straw that breaks the camel's back. If new lights cure your algae issues, just remember, you are still on the ledge as far as nutrients and water parameters are concerned. The small spectrum shift in an older t5 bulb just pushed you over the edge. If you had control of the nutrient levels and other needs of nuisance algae, the small spectrum shift in your old t5 wouldn't even be an issue. JMHO.

 

[billsreef]

I know this was an comment made almost 2 years ago. I just saw it. And my understanding is that the blue and shorter wavelength end of the light spectrum, like UV, penetrates the water better than the other colors and they all have virtually no problem getting down 2 feet in an aquarium.

"This applies to aquariums when we consider the light spectrum and how it applies to our aquariums individual needs: Red light is the first to be filtered out and can only penetrate a short distance. As light waves penetrate deeper into the water, orange and yellow are lost next. Of all the colors of the spectrum blue light penetrates the deepest. Corals need intense equatorial UVA (actinic) as well as other aspects of PAR. "

And I'm not saying the OP ideas about light is right or wrong. I think they may have a nugget of validity but there is so much more that plays into the development of cyano bacteria, like carbon for food and water flow along with lighting issues. Personally, I think the OP's idea of the reason cyano starts at the ends of the tank (if than assumption is even correct) is due to water movement, or the lack of it, at the ends of the tank.

Ron, you need to look at the germecidal wavelengths, UV C, not blue light in general, or even UV A and B (which do penetrate water more than the UV C). Just think for a moment, common window glass filters out most UV (A, B and C), yet plenty of blue light comes through. Water has the same effect, though the UVA and B will penetrate several feet, though much reduced from the surface.

 

[REEForBANG]

This is a really good thread especially for us Flourecent bulb users.

 

[Timfish]

Has any one actually taken some readings? There are meters that will look at wvelengths both shorter and longer than visible light. Even a PAR or lux meter may show higher light readings in the corners than in the center, remember light entering through the surface and hitting clean interior sides will have near 100% reflection, this potentially could increase light levels in the corners significantly.

 

[Aqualund]

wow such an old thread. Looks to me like poor water chemistry caused their cyano issues, not the light spectrum.

 

[SavingOurSeas]

Anything is possible, a great thought; however, water parameters would seem to me to be the most likely culprit. Definitely keep experimenting with this. I'd love for this to turn out to be a fact. It would be such an interesting find.