LED SPS keepers. I need your suggestions.

[kevin_e]

I have a 20 gallon SPS aquarium. It's been setup for 2 years now under metal halides. Due to the heat of the halide in my apartment and the upcoming Florida summer, I will be switching to LEDs.

What kind of optics would you recommend? I am considering only putting optics on the blue and white LEDs. My theory is that the color LEDs weill get more coverage without them. Sound logic?

My biggest issue is the color combination. I want to make sure I have a strong spectrum. I know many feel iffy on LEDs and SPS, but I have seen tremendous local success and I am of the belief that water quality has contributed to SPS/LED myths (but let's leave this topic for another thread).


These will be Cree LEDs and Meanwell drivers, by the way.

This is what I am considering (the cool white is actually warm white, it's a typo):

[dadummy]

FWIW, I have a 20 gallon with DIY LED that is used for frags and a QT tank. Started out with 6CW@ 1050ma, 6RB@700ma and 60 degree optics. Whites washed out the blues. I then added 3 Blue@700ma and 4 UV@700ma with same optics on the RB driver. Whites were still too much. I then removed two CW and replaced them with two RB@ 1050ma. Color was better but the whites were still too intense. I recently switched the 1050ma driver out with a 350ma driver and corals are much more happy.
Red planet frags have green in them instead of being solid red. Rics and zoas are open more along with the sps.
I have not run any warm white or neutral white, which from reading look better.
Have been working on a DIY LED for another frag system and went with some 10w Blue and RB ,four of each. I also purchased 10 1w UV 420nm from fleabay and gave them a shot. Have all ten running on a cheapo 300ma driver. I was surprised to see what a difference the make, stand alone they aren't much, but mixed with the blue and royal blue you get an extra pop.
If I was to redo the 20g, which may happen in the near future, I would add ten of the UV, and try some neutral or warm white

don't know if I answered any of your questions but that is my experience with a 20g and LED's

check them out here

http://www.ebay.com/itm/10pcs-x-1W-UV-High-Power-LED-Light-Emitter-Violet-Purple-20mm-star-pcb-base-/231058510738?pt=LH_DefaultDomain_0&hash=item35cc291392

[kevin_e]

Thanks. Any input is valued. I appreciate your insight on the cool whites, that is a temperature I will want to stay away from.

Did you have the whites at 100% along with the blues?

[kevin_e]

I want to share some thoughts on LED selection. In return, I would like you to bounce your thoughts off of mine and hopefully in turn, we can narrow in on the right spectral combination for my needs. I am in the process of selecting the right combination of LEDs for my SPS reef aquarium. I have been given some tips from others in another thread, and I truly appreciate it.



Let's look at white LEDs first. We have 3 options available to us. We have the Cool White (5,000-8,300 K), Neutral White (3,700-5,000 K) and Warm White (2,600-3,700 K) diodes it's commonly believed that photo synthesis strongly favors a color temperature of 6,500 K. So with that in mind, cool white appears to be the best option for white light LEDs.



With color LEDs, I want to look at this spectral graph showing the absorption rate of light for stony corals at particular wavelengths.



http://i1212.photobucket.com/albums/cc445/Kevin_Easton1988/Untitled.png (http://s1212.photobucket.com/user/Kevin_Easton1988/media/Untitled.png.html)





As you can see, there are spikes between 450-500 nm, with a rise in absorption rate beginning around 400 nm and decline ending between 500-550nm. There is also a spike at about 670, with a rise in absorption rate beginning around 650 nm.



With these spike in mind, let's look at the colors that favor these spikes:



Violet- 410-420 nm

Royal Blue- 450-465 nm

Cool Blue- 465-485 nm

Cyan- 490-520 nm

Deep Red- 650-670 nm



The majority of the peaks occur in the Royal Blue wave length, which to me, would make this the most important and most numerous diode in unit. All four of the above diodes occur where the majority of the spike occurs on the shorter end of the wave length spectrum. To me, all 4 colored diodes would be important to achieving a complete spectrum.



The other peak at about 670, with a rise in absorption rate beginning around 650 nm, is similar in the range of the Deep Red diode, also making this wave length important.

[dadummy]

that's a good analysis, definitely doing your homework.

the above stated current is what the LED's are being run . No dimmers, only on/off

as for the above post, I would say RB is the most important as well as the lower end of the spectrum.

Not sure the specifics but as sunlight penetrates the ocean at a certain depth all that is left is the lower end of the spectrum. I believe red is the first one to go.

On a 150g that was running T5, I switched to all LED. It was RB and CW at a ratio of 2:1.
Once again the cool white washed out the blue. As for the sps, Montipora , Seriatopora did well, along with some Acropora. Millepora was one that did not do too well under LED alone.
I then added some blue LED to see if it would help, I noticed in the frag tank that the rainbow monti had better coloration under the Blue Led.

I am currently running 56RB, 14 Blue with the addition of 3 80w ati blue plus t5 and one KZ 80w Fiji purple. The cool white Leds have not been on in months. The Fiji purple has some of the higher end of the spectrum, as I believe the blue plus have a small spike.
However the sps colors are fantastic and growth is pretty good. With "blue" being the predominant spectrum

Another thought it not only keeping the coral happy but yourself as well, finding a combination that pleases your eye.
The beauty of a 20g is you don't need to break the bank on Led and if you wanted to switch a few it would only cost a few bucks

The wavelength for NW and WW led, do they cover any of the 490nm-670nm range?

I don't know.

Intensity of the LED is another factor, one could blast a 20 gallon with a 100w chip or run an array of 1w chips. People running dimmable fixtures run the whites at say 50%, if max drive is 700ma then they are running at 350ma or 1w, so that could be another factor is choosing your components.