LED Lighting.

[10gnano]

so how do i find out what spectrum my light is in?

[Hookup]

so how do i find out what spectrum my light is in?

THAT is the first part of the LED problem.  The second is, how do you know when it shifts!  Anyone building these really needs to think about using something other than their eyes to measure spectrum of the light produced.  PAR isn't going to get the job done either for that matter, got to be spectrum.

[Vincenzo.]

well i guess im just going by other peoples readings. and i hope they are right. i think led is/ and will be the new light of the future. everything will be led. even tv's now are, newer car lights, everything..slowly.

[Hookup]

No question Vince.  LED's are in all likely hood going to be the new lighting systems for our tanks.  They range of application seems almost unlimited.  Just at this point, we do not have any good spectral analysis of the LED systems, both at the time of inital "fireup" and at some point down the road. I would hate to shell out a few grand for an LED system only to find out that within 6months they spectrum shifted and has made the output far less effective.  The going-in point for LED's is that they have such a long lifespan, their capital cost is mitigated when compared to the maintenance cost of MH or T5 or VHO systems.  But the thing that you are gaurenteed to get with a "traditional" light system is a "fresh" bulb, or reset spectrum, every time you change bulbs.  With LED systems we are hoping that the spectral shift doesn't happen until after the cost is recovered.

All of the data that I've seen only talks about life-span of LED's.  That's like saying the MH bulb will last for 3 years.  Which I think it will, maybe even longer.. but we all know that after 10 or 12 months, the MH bulbs shift spectrum so much they are detrimental to our tanks.

When it comes to LED's we just do not have the data to make me want to leap on it.  It's all based upon hours of "luminance" not spectral output and shift, heck, or even PAR would be nice.

[Vincenzo.]

very true u can have a bulb for 10years dont mean its any good. though i did read that after 7 years of a led life, it's running at 70% of it's spectrum capacity. i'll try and dig up the info. each night i go through about 20-30 pages and never save anything. so if i come across it again, i'll quote it up. plus i dont plan on spending 2500$ on a 48'' light, but rather a diy one for about 150-250$ but maybe even cheaper, since i might get some stuff for free for the project.

[GSM]

Hi Vince,

Thanks - the blue array I built to supplement the halides does the job nicely.

I also built a 24 LED (12 blue/12 White) setup over a 20g frag tank in the basement.  Basically 1/2 of Soundwave's design.  Cost me about $250ish including shipping.  So far the corals are growing just as good as under my older 4 bulb T5 setup.  I have both SPS (monti's) and softies growing out.

Next build will be using a dimmable ballast that I want to control with my Profilux...

I'll snap some shots maybe this weekend.

Cheers,

Greg

[10gnano]

Not sure what LED's you guys are buying, and where you are getting them from, but what I can tell the only difference between one LED and the other is the colour of the light, and they are dirt cheap. 250 for a 24 LED setup seems really expensive, unless i am buying the wrong kind, I would love to see a picture of the ones you guys are using

[salvini55]

They are special LED's, not the cheapos you may be thinking of + the power supplies, dimmer, reflectors....ect.. it adds up

[10gnano]

An LED is An LED, I dont think you can dimm an LED Either, but in anycase I am going to try and build one and see what it looks like, My LED's are a very Crisp White, and I have some Blue as well

[RossW]

I also built a 24 LED (12 blue/12 White) setup over a 20g frag tank in the basement.  Basically 1/2 of Soundwave's design.  Cost me about $250ish including shipping.  So far the corals are growing just as good as under my older 4 bulb T5 setup.  I have both SPS (monti's) and softies growing out.

Greg -

Excuse the possibly obvious question... Is there anything out there which supports 24 LED's being able to replace 4 t5 bulbs?  If so, how many do you think you would require on a 48" tank.

Ross

[Hookup]

Not sure if all LEDs can do this but most LED's I've seen can be dimmed.   The ones that are pre-built into aquarium lighting actually have wicked cool controllers so you can "tune" how much of what LED's you want on in terms of 0-100% power rating... if it's too blue, just power-down the blues a bit... if it's not white enough, power those up further... very cool stuff.

There are many LEDs each with their own spectrum.  The thing that I've read about is that they cast very focused beams of light, or at least some of the ones I read about do.  People were using prism type devices to broaden the distribution of light so they didn't have to pack in a bazzillion of these LED's to create a uniform light source.  That introduces a whole other cost issues, not even to mention the possible spectrum/output issues that could be associated with it.

[Vincenzo.]

Not sure what LED's you guys are buying, and where you are getting them from, but what I can tell the only difference between one LED and the other is the colour of the light, and they are dirt cheap. 250 for a 24 LED setup seems really expensive, unless i am buying the wrong kind, I would love to see a picture of the ones you guys are using

^ u cannot use 1/4 watt leds or 1/2 watt leds, but 1watt + ..
so you are using the wrong leds.

look up>> CREE XR-E Star
^^thats what you want.

An LED is An LED, I dont think you can dimm an LED Either, but in anycase I am going to try and build one and see what it looks like, My LED's are a very Crisp White, and I have some Blue as well

^a led is NOT a led. thats like saying all CARS are the Same.
white led you need 6500K +

Greg -

Excuse the possibly obvious question... Is there anything out there which supports 24 LED's being able to replace 4 t5 bulbs?  If so, how many do you think you would require on a 48" tank.

Ross

^for a 48'' fixture you want 48 leds.


.
.
.
& yes LED's CAN be dimmed.

[GSM]

Hi Ross,

I haven't found a study on LED vs T5 or MH but I'm seeing decent growth on the Monti's and Softies in my grow-out.  No idea for clams and other more light sensitive corals.

I'd use at least 24  3 watt LED's per 2' of tank for softies and hardy sps.  You can squeeze in more but it is easy to bleach corals if higher up in the tank, especially if using optics on the LEDs to focus the light.  This is where dimmable option is key - it also helps set the blue/white balance.  The buckpucks I'm using are dimmable.

It's the setup I was showing you this past summer - I think I had the heatsinks in the vice when you were over.

Cheers,

Greg

[Vincenzo.]

for that many 3w leds u will need a heat sink n fans.

[salvini55]

Anybody check out this thread on RC about LED supplimentation? The pics are breathtaking and the cost is very low!

http://www.reefcentral.com/forums/showthread.php?t=1715182

I like how they are water proof and compact so you can hide them easy. Im waiting for some more photos and write ups untill i buy some myself.

[GSM]

for that many 3w leds u will need a heat sink n fans.

Your right Vince.  You want to keep them cool so they'll last. 

[Canoe]

A few points on NOT driving LEDs at their max, and another reason for dimming drive circuits.

Running an LED at it's maximum drive current / brightness will decrease it's life and cause more of a decrease in light output and the resulting shift in colour spectrum. Drive it at 70% and get ~double the life, less fall off and far less shift. Downside, you need more LEDs to achieve the same brightness.

You can use a fixed output power source to provide the 70% drive, but if you use a variable/dimming circuit and turn it down to drive the LED array at 70%, then over time when the fall off in light output occurs you can up the drive to, say, 75% to compensate.

If your "whites" and "blues" are on separate circuits, then when the whites fall off you can up the white and lower the blue to somewhat compensate for colour spectrum. If you have an additional red/orange circuit, you can up their drive to warm up the colour temperature.

For a few: LEDs are not themselves "dimable", but we get a light dimming effect with LEDs by varying the drive current or by pulsing the drive current (from near zero to even max) at high frequency (LED looks like it's continuously on). Pulsing is great as it runs the LED at a much cooler temperature.

Cooling LED arrays:

For my design, I'm considering mounting the LED devices electrically isolated (normal mounting for these) onto the underside of a sealed Al box around 2" high and the area of the LED arrays. The box would be the heat sink. The box would have 1/4" of distilled water in it. The Al box will function as a "heat pipe", a device that uses latent evaporative pressure to distribute heat energy within it (they only work at temperatures under the pointing point of the liquid used). Like the flat heat pipes used to even thermal loads on CPUs, the heat from the LED devices would be evenly distributed throughout the box. Like the tube shaped heat pipes (used to take heat away from various electronic devices), the "heat pipe" function of the box will conduct the heat energy to all of the surfaces of the box. Add heat sinks to the top and rear of the box (sides and front if you don't mind the look) and the heat should be able to be dissipated without the use of fans (which generate noise and additional heat). The LEDs run the coolest possible and have the greatest life and least colour shift.

[Vincenzo.]

to much work when u can get fans that are noiseless and close to heatless. And y not run them at 1000mA. As long as u have fans and heatsink ur fine. And big deal if they burn out after 5years-8yrs. Thats 5 yrs of bulbs paid off the fixture after 2-3yrs. +what u save in hydro. And from what i have read after 5-8 yrs they go down to 70-90% from 100%, once again it paid itself off. My project is a total of around 200$. Thats 1.5 mh bulbs over 16months... Oppose to 5-8yrs at running at 100%...i think ill run my leds at 1000mA

[Hookup]

Something I stumbled across that had cool photos and LED's... therefore it must be relivant to this thread right??? haha...

http://www.reefcentral.com/forums/showthread.php?t=1715182

No idea if that helps, or is even in the same ballpark as what you're discussing.. but it's got pretty photos.

[Vincenzo.]

ya i think its just more or less moon light. At 0.01 watt they are useless. For me putting 120 leds in a 8''x8'' impossible.