My T5's shimmer???????

[Viva'sReef]

Was wondering what everyones take on this is......I just installed a new ATI sunpower over my shallow reef and it shimmers on the bottom, and on the Rock scape just like my old MH did.

When people say T5's do NOT shimmer, what exactly are they referring to? Because I am getting shimmer all over the tank

 

[drainbamage]

cheap T5's don't shimmer- they don't produce enough intensity to cause it. The high-end T5's do, which is why I'm a big fan of saying "not all T5's are the same," even though it ticks off the people who bought cheap T5's :xd:

Main thing that'll help cause shimmering though is highly disrupted water surfaces- the more ripples the more shimmer (as that's what's causing the light difraction.)

 

[patent]

Bottom line: Do you like it? If your happy then you have the right lights.

As to the shimmer, I have a tank with a mixed T5 MH setup. I do get some variability with just the T5 on, but not as much as with the MH on. The T5 lights typically run the length of the tank, and thus provide a linear light source and if you have several bulbs across the depth of the tank even more so. The MH is more like a point source, so when a wave passes underneath the MH, the "point" (using "point" for simplicity) sees the water source change and it refracts differently due to the different angles that the light hits the water/air interface at as time changes. This is less pronounced for a linear light source than a point source.

More surface agitation should lead to more shimmer, and a more "point" sourced light should lead to more shimmer. You can have some with T5, certainly, and theoretically alot in some tanks.

 

[gar732]

When I used to run 10Ks I got a bit of a shimmer from them. The combo I have in there now (all ATI) is more blue and I get almost none. At that its only noticeable on the back wall and not on the sandbed.

 

[butts182]

is it more than just the surface aggitation?

 

[drainbamage]

is it more than just the surface aggitation?

definitely more- check out Patents post above, it describes it all pretty perfectly from a physics standpoint.

 

[patent]

is it more than just the surface aggitation?

Yes, I don't have a formula, but surface variability/rate, intensity of the light source, and the size of the light source all play in. I would expect water clarity and depth would as well, and I'm sure I'm missing things.

 

[Viva'sReef]

I had always been under the impression that all T5s would not create any shimmer effect at all. I was worried about selling my t5/mh combo fixture for all t5's for that reason. It would look dramatically different.

A little more info from my tank.....it's very shallow, 12" shallow lol. Surface agitation is very turbulent since I can't place the pumps very low without disturbing the sandbed more than I already am. While all bulbs (6) are firing the shimmer is less noticeable but remains slightly. It's when only 2 bulbs are on I notice dramatic shimmer lines on the sand and edge of the stand (1.5" lip around front and sides).

Bottom line is I'm happy your right.

 

[skinz78]

Very interesting, I have had quite a few different T5 setups and haven't really had much shimmer at all.

drainbamage, when you say the more expensive T5 setups will are you referring to the bulbs or the actual fixture? I currently have a 4 bulb setup that is overdriven by 15 percent and I would think if possible this setup would be my best bet for getting the shimmer? I do have some shimmer but that is from my stunner strips IMHO.

 

[Viva'sReef]

Don't get me wrong here guys, my shimmer effect is no where near as dramatic or "crisp" as with MH, but it's there.

I just thought it would be like a florescent lit office space.

Fwiw if I shut my pumps down and the tank is still, the effect goes away entirely. The surface agitation is the key here for me I believe. Less light intensity so to not drown out the refraction of light occurring from the water surface.

I wonder if using dimmable T5's would enhance the effect further?

 

[Viva'sReef]

As for the fixture...I've noticed the highly reflective SLR on the ATI blows away the ones on my old current outer orbit contributing even further.

 

[drainbamage]

I've always been fascinated by light and it's properties- but I've never pursued any form of formal education on the subject beyond the basics that are taught in the calculus based physics series I've taken, so please understand I'm no expert, nor using accurate terminology or descriptions, just trying to share what I understand or believe on the subject.


Basically start with what Patent said- he's got the basics of the subject neatly sumarised.

Essentially "shimmering" is caused by the deflection of the light-wave into pieces that arrive at the location at different times. You're basically getting each "wavelength" difracting to some degree, creating layers of different colored light. So to get the best shimmering, you want a few factors:

-- an intense source of light- this is why halides/LEDs are best for shimmering- you have a small "point" of light that has a high intensity. As the light travels from the point source, you'll have greater separation. With fluorescents, you have an even blanketing of light, and the interference between the light output negates (deconstructive interference) the separation of the light. Thus you see less shimmer when running all your lights then when you're running just a couple. Not sure how the coloration totally comes into play, I do know the best shimmering under T5's occurs with the bluer spectrum bulbs, even more so if they're placed further apart (I get best shimmering when the outside pair of bulbs is lit on my teklight than I do with the inners.)

-- Agitation of the water surface to cause difraction of the light waves. Essentially each different curve of water that the light encounters acts as it's own prism, casting the light upon a new angle. This creation of many angles is what helps us achieve shimmering, especially with less intense/focused light sources. With still water, the light is all roughly bending in the same way, so the light all falls upon the same location regardless of the angle of bending that's being created.


My comments on the more expensive T5's is a reference to the power of the ballasts as well as their reflectors- IME both are vital to getting maximum output of the bulb. While higher quality bulbs should achieve better shimmering (the more pure wavelengths being produced yield the best separation of light, while the lower quality bulbs often have overlapping colors which cause deconstructive interference,) the bulbs are secondary to the intensity of which they are being lit and focused. Obviously pushing more power through the same bulb will create more agitation of the gases inside the bulb and put off more light, hence the more expensive fixtures tending to be visually 'brighter.' I've yet to play around with a PAR meter to find out how much of the increased intensity from the overdriven fixtures is actually usable, but from my experience, it is related.

-=disclaimer=- I wrote this based on my limited understanding and experience, if you see errors, please kindly correct me as I'm obviously still learning, I'm not trying to present any of this as concrete facts, so please also only use it as information of such quality (or lack thereof :xd

 

[patent]

Surface agitation is very turbulent

definitely leads to more shimmer.

While all bulbs (6) are firing the shimmer is less noticeable but remains slightly. It's when only 2 bulbs are on I notice dramatic shimmer lines on the sand and edge of the stand (1.5" lip around front and sides).

That matches my understanding.

Just a pure guess, but if you get good shimmer with 2 T5 bulbs, I would almost guess that MH would be distracting at first as the shimmer could be too much at first.

 

[patent]

Good post DB.

Not sure how the coloration totally comes into play,

2 things, overall intensity of the bulb, and how broad of a spectrum it kicks off. This is just an expansion of what you said.