Not Quite Sold on LED Lighting

First, for the cost of a cheap LED fixture, I can buy 5 years worth of T5HO bulbs and have enough change left over for a couple cases of beer.

Then there's this:

http://www.youtube.com/watch?v=wjEjXD0J2eM

http://www.youtube.com/watch?v=yoFVuAy5MNU&feature=related

It was noted that the 2 frags were placed where the PAR was the same in each tank. The difference in only 8 week's growth is amazing.

And lastly, there's this thread:

http://www.3reef.com/forums/inverts/rbta-odd-observation-lights-129500.html

I think I'll wait until the technology has proven itself long-term.

 

videos aren't working...;never mind

Just watched the videos...While I agree that LED's are probably not currently at the same level as MH's, I have to say that their test was not very compelling.

I would like to see a test like Steve Wright did for the carbon dosing but with lighting as the variable over a longer time frame than 8 weeks.

 

How do you figure? A photon is a photon. It does not matter if it comes from an LED, metal halide, fluorescent light, or magic pixie dust. If you have the enough photons, of a spectrum useful to the zooxanthellae, corals will grow and be happy. If you don't they won't. LEDs however, actually can have a broader spectral range than halides. If they don't, it is because the manufacture chose to use ones that didn't. Generalizing to "LEDs" doesn't really seem to be a fair comparison.

 

I agree but like you said, the key is the spectral range. I said 'currently' because the spectral output is still a fairly significant variable for LEDS, once they are more constrained, LEDs will clearly be a far super option. Are there actual comparisons of the spectral output between the two?

 

^^ only leds... since inception. And it's rocking. crappy pic granted...


a photon is a photon... LEDs being cheaper can easily be debated. As far as them working.... the proof is all over this forum.

 

Yes.

http://www.3reef.com/forums/led-aqu...larger-bridgelux-few-chinese-leds-129292.html

That thread then take those and compare them to any you find on a particular bulb/ballast combo... like these.

Feature Article: Spectral Analysis Of 400w Lamps: XM, Radium, Osram And Sunmaster, PFO — Advanced Aquarist | Aquarist Magazine and Blog

And you will actually find them to be very similar and LEDs may even have a spectral advantage. The biggest problem is acclimation. People think of PAR as an exact value and its not. Par readers over compensate for Reds and greens and under compensate blues. So they tend to underrate blue light. Something that corals are the best at using and leds are the best at giving. PAR meters are great tools but aren't particularly good for measuring light from different sources like that. It's not giving an apples to apples comparsion.

 

^ yes but how much better would your tank be if you were running metal halides? haha j/k

I think led's are the bomb, they rock. There is no denying that they work wonderfully well, but the question was are they equivalent to metal halides in terms of growth.

While the testing done in the video was pretty simplistic and there were lots of errors, this question is still a valid one.

Looking at 1:1 RB and CW spectra for LED's versus a metal halide you see alot of differences. The goal now for leds has been to get the wider spectrum using various colors and the jury is still out on what combinations work best, so that is why I am saying currently they may not be as good as metal halides.

I am not saying that they are not good, they clearly work very well, I just think that there is still room for improvement on spectral blending. Once that is done, they will be equivalent to metal halides in terms of light, but the added benefits of heat, modularity, programming etc will make these fixtures the obvious choice.

 

Both are too broad of terms... What leds verses what metal halide? If you got the very best in the led world and put it against the very best in halide world it would be close enough that the other parameters in the tanks would have to much of an effect to ever really tell. Point being, it's close enough to not matter. Of the people in my reef club, I am getting exceptional growth same as the metal halide people and deal with less headaches.

 

the MR. saltwater tank experiment was whack... The tank went through major problems and both sides ended up crashing. There was nothing about that experiment that went right. The guy lost almost all his sps by the last update he did (on the metal halide and led sides)... (he kept adding more results in the comments section back when that was going on) I was shopping leds at the time so I payed close attention.

And a Boost LEd is no where near equal to a 250watt MH... use the people on here that are obviously successful with leds. There are a TON of us. Myself, FaceofDeceit, evolved, rocketman... just to name some that come directly to mind... look at all those build threads and see the success.



Look at the newest MR. Saltwater tank experiment if you want real results. He used his OWN tank, a properly maintained tank that had one half with halide and one half with led and saw no differences. The led side continued to look as good as the metal halide section and he eventually went all led on his own tank. (prior to selling all his equipment and moving to TN)

 

There are too many variable factors when it comes to LED's spectrum. And the diodes have to be right next each other to get spectrum mixture.

I still think MH or powerful T5s is the way to go in comparison to LEDs. However I thought Id hate it from my heart if I have to change the bulbs in short period of time with the higher monthly electric bill and heat. Just couldnt justify all that, so I went LED.

Whats important me:
-Dimming option
-Color blend option
-No regular bulb change
-Weather simulation option
-Sunrise/set option
-Lower monthly electric bill

MH is:
-Proven coral growth
-Proven inverts preference (clams, anemones etc)

If you do it right (mainly spectrum wise), you could simulate the MH with LEDs. Im in the process of proving it!