LED's as a Primary Light Source

I am very interested in using LED's as the primary light source in a reef tank. Does anyone know if LED's have what it takes to support corals? I have a 26gallon bowfront tank that I am in the process of setting up, I am currently building the stand and canopy for it. I am planning on lighting it exclusively with LED's. Im hoping that I have enough already but I guess Ill soon know the answer to that... Currently I have 3 at 5watts each and 450nm, 3 at 5watts each and white(they look like a 12,000k metal halide) and then I have 8 at 1watt each in white as well. So far from breifly playing with them, they seem to give the same shimmer effect that you get from metal halides, Im just hoping that they support corals the same as well. From what I have researched, they are the brightest LED's in the world that are currently available. The tank will be setup as a nano reef with a 14gallon sump and 1 1100gph circulation pump with multiple outputs. I hope to be able to support some soft corals as well as a good variety of hard corals. Does anyone have a recomendation for a good skimmer to use on a small tank, something rated at at least 75gallons, I was thinking of using a smaller excaliber skimmer as the large ones work well.

[Beverly]

Just read an newspaper article on LEDs. Reserachers have finally achieved "white" light with them, though I have no idea what application they would have in marine aquaria. LEDs are supposed to run for a fraction of the cost of any other type of light, a good thing in their favour.

I'd suggest you do a ton of research on them, if such research material is available on the internet yet, and report back your findings. LEDs could be a promising lighting alternative for us reefkeepers.

BTW, have been reading about the Kelowna fire in the paper today and yesterday. Sounds really freaking brutal for folks out your way Hope all is well with you and your loved ones

[MalHavoc]

You may be interested in reading the article by Mike Kirda in this month's Advanced Aquarist:

http://www.advancedaquarist.com/issu...03/feature.htm

He shows some PAR readings from a LED-lit tank that was showcased at IMAC this past year. The tank uses 3 LED bulbs totalling 13 watts, with PAR readings of 235 mE/m2 above water, 160 immediately below water, and 24 mE/m2 on the bottom of the nano tank it was used on. This tells me two things - one, LEDs are pretty bright, PAR wise, but they seem to lack the punch that other types of lighting have, like MH. The tank featuring 2 x 400W Ushio bulbs with 3 x 110W VHO actinics has PAR readings of over 400 just below the water surface, and drops to the mid-200's near the bottom of the tank.

[Beverly]

Originally Posted by MalHavoc

The tank uses 3 LED bulbs totalling 13 watts, with PAR readings of 235 mE/m2 above water, 160 immediately below water, and 24 mE/m2 on the bottom of the nano tank it was used on.

The tank featuring 2 x 400W Ushio bulbs with 3 x 110W VHO actinics has PAR readings of over 400 just below the water surface, and drops to the mid-200's near the bottom of the tank.

This sounds like comparing apples to oranges to me.

LED watts totalled 13, MH watts totalled 800, and VHO watts totalled 330. The comparison would be more valid, imo, if 800 LED watts were compared to 800 watts of MH, and if 330 watts of LED were compared to 330 watts of VHO.

THOSE would be a valid comparisons.

Research on, deepblue!

Ive done alot of research on them and have found that everything points to them working very well. The only thing I cant find is any actual use on an aquarium with corals.

[MalHavoc]

The point is, watts don't really mean anything (they never have, actually). And yes, it is meaningful - compare the PAR values at play here, which is all that really count anyway. Examine the system with 4x96w power compact bulbs - initially, it has less PAR than the 13 watt LED set up, but penetrates far deeper and the PAR rating at the bottom of the tank is higher than that of the LED. Corals don't care if the source is a 1000w Ushio bulb, or a 10w LED bulb - what counts is the PAR reaching them.

When the time comes, a system consisting of hundreds of watts of LEDs will certainly be impressive. All Im saying is that an LED system lacks the punch of other lighting systems, even if the initial PAR readings are higher, at least for now.

[MalHavoc]

For the record, in addition to comparing LEDs and MH systems, we can also look at differing photon flux densities of various MH bulbs at different wattages to further illustrate that PAR is what counts. Sanjay Joshi has measured 400w Radiums and 250w Iwasakis numerous times in his series of articles over on Advanced Aquarist and also on the Animal Network. Initial measurements for a 400w radium are 116.2, and for the 250w Iwasaki, 116.1. Almost identical light output (at least initially, the radium drops pretty fast, whereas the Iwaski actually goes up for a few hours), yet the Radium is a much higher wattage.

http://www.animalnetwork.com/fish2/a.../2/default.asp
http://www.animalnetwork.com/fish2/a.../2/default.asp

Some interesting stuff.

[Beverly]

Originally Posted by MalHavoc

The point is, watts don't really mean anything (they never have, actually). And yes, it is meaningful - compare the PAR values at play here, which is all that really count anyway. Examine the system with 4x96w power compact bulbs - initially, it has less PAR than the 13 watt LED set up, but penetrates far deeper and the PAR rating at the bottom of the tank is higher than that of the LED.

Though you may be perfectly correct in your comparisons of PAR for 13w of LED to PAR for 4x96w PC, I will only accept the results when 13w of LED are compared to 13w PC in the same tank, or when 384w of LED are compared to 384w of PC in the same tank. I still sounds like comparing apples to oranges to me to compare such vastly different amounts of light to each other.

[MalHavoc]

Thats my point, though. the lights aren't vastly different - don't compare watts, compare PAR, which is what light really is. In these cases, despite the wattage of the LED being so low, the PAR values are suprisingly high. I agree that this bodes very well for the future of LED. I also agree that I'd like to see a comparison of 250 watts of LEDs versus a single 250w MH bulb. I've already seen some hoods with dozens of LED bulbs and the results are very impressive. The wiring scheme isn't so much fun though

[Troy F]

Darren (DJ88) has done quite a bit of research in to their viability and I think he said at the present it's still not cost effective at this time but that they would work if you could afford the amount needed to light a reef.