LEDs and reef tanks

I'll admit up front that I did not do a search to see if this topic has been previously discussed. So please feel free to point me in the direction of the thread if it has... and I'll even overlook any /ubbthreads/images/graemlins/twakfl.gif that you may want to throw my way too for being so lazy... /ubbthreads/images/graemlins/blush.gif

My daughter has a saltwater reef tank set up in her apartment. She has coral. She is trying to find the best lighting for her tank and came upon an article that mentioned LEDs as an option. Because I have trained my daughter so well (she really HAS been listening!! /ubbthreads/images/graemlins/grin.gif ), she called me for more information and asked me to ask you guys what you know about this unique use of LED lighting.

So what do you all know? Thanks in advance for any and all information... /ubbthreads/images/graemlins/thumbsup.gif

can't she register herself? /ubbthreads/images/graemlins/poke2.gif /ubbthreads/images/graemlins/grin.gif

Sasha:
Here are a few links

http://www.petco.com/product_info.asp?webt=0&tab=3&SKU=6048200036&cm_ven=SE&cm_cat=frg&cm_pla=82&cm_ite=6048200036

http://store.yahoo.com/worldpets/hilledmod.html

http://store.yahoo.com/worldpets/hilledsys.html

Hope this helps - though I do like Roths idea /ubbthreads/images/graemlins/grin.gif

It's been a few years since I kept a reef tank, but the thing was that you needed a LOT of light (like at least 20,000 lumens for a 50 gallon tank) And it needed to be of a high color temperature. So white LEDs would be OK in the color temp category, but developing a lot of light with LEDs would be very expensive - Do you really want to have to install 1000 1 Watt luxeons? Not to mention that the efficacy of white LEDs is pretty dismal compared to fluorescent and metal halide, so the energy cost to run them would be pretty high.

But, a few white luxeons might make a very nice low-level light for use at night in a darkened room.

I do remeber a thread around here about this.
I'll see if I can find it.
I think the conclusion was that LEDs just didn't quite fit perfectly.....but my memory is pretty darn short...

Edit:
Found two while looking for one.
The extra is Aquarium night light
The one I was think of is Salt Water Aquarium

Roth... her laptop was stolen by her ex-tweeker-roomate... /ubbthreads/images/graemlins/icon6.gif

Stainless... funny you should post that article from Petco... she is the aquatics specialist at the Scottsdale Petco... /ubbthreads/images/graemlins/wink.gif ... that's where she got the idea for the whole "moon-light" thing with LEDs... /ubbthreads/images/graemlins/grin.gif

brickbat... I think that's what she's looking for... the whole night-time thing... moonlight.

wow, that does suck /ubbthreads/images/graemlins/frown.gif

he does know who you and your husband are right? /ubbthreads/images/graemlins/thinking.gif
very stupid kid...

Roth... yeah... he knows. But as you pointed out, he's not the brightest bulb in the string. /ubbthreads/images/graemlins/icon6.gif

Most white LEDs is a blue emitter with yellow phosphor. It's spectrum consist of peaks at the blue and yellow colors. This is not good enough for corals, anemones etc. High color temperature( around 10K) Metal halide(HID) bulbs are therefore more suitable for proper growth of the tank inhabitants. Beside that, current LEDs is still lower in efficiency than metal halide technology. It will be more expensive to run and to have equivalent light output as a 250W MH bulb will require a LOTS of luxeon and it's going to be very expensive! If you have a large reef tank(250gallons or larger), you will need more than 1000W of MH lighting. Of course, this depends on what types of corals you keep, how deep is your tank and where you place it, etc.etc....

Currently, LEDs' role in a reef tank are mainly as a artificial moon light. You can use blue or white LED depending on your preference. Blue LEDs will cause some corals to glow nicely but white LEDs will look more natural. If your daughter is good with electronics, she can even design a circuit to control the brightness of the LEDs to mimic the effects of moon phase. This will stimulate the sprawning of corals etc in your reef tank.