LED clarification

1) You might want a few more. I would bump it up to 48 myself. What are you keeping?
2) Since you are going DIY I would just use aluminum C channell (aka U channel). It's cheap, effective, and easy to work with.
3) Optics will depend a lot on how high you are mounting and how spread out the bulbs end up being. 60 and 90 degree optics SEEM to be popular. I don't run any, but my lights are maybe 2-3" from the water.

 

Yes, I would say to bump it up also to 48, Just make sure the drivers can handle the load. This way if you ever decide to upgrade to a larger tank, you are already covered.
As far as heat sinks, Definitely use quality heat sinks.
1. The efficiency of an led goes down the hotter it gets.
2. As the efficiency goes down so does the out put of the led.
3. The cooler you keep it the longer it will last.
I would use 2 - 4.25" x 16" or 18" pre drilled Heat sinks, not sure how many each one holds?
As far as optics go, I would run 80* or none at all. Unless your tank is more then 24" tall, I would not run anything more focused then 80* as it becomes to much of a spot light effect.
This is just my two cents worth, hope it helps and good luck. Keep us posted as we love DIY projects!

 

I thought i would link to here in order to get more opinions and ideas regarding the overall color appearance of LED setups. There has been quite a large conversation going on over here,http://www.reefcentral.com/forums/showthread.php?t=1885076 and i think this concerns nano owners as well.

It basically addresses issues with missing spectrum and colors with the popular Coolwhite, Royalblue combo and discusses ways to improve overall color and performance.

Any thought or opinions will be appreciated on here or over there.


HERE IS A SUMMARY OF THE ENTIRE THREAD TO SAVE YOU WEEKS OF YOUR LIFE. CREDIT GOES TO SYNCHRO



Here is my attempt to summarize this thread and others I've read on LED asthetics. I've copied and/or paraphrased from your posts to make this thread more accessible. I hope this is ok, let me know if you want any of your words removed.

Color

Warm Whites (WW) - Very warm. Difficult to blend with bluer colors. Not commonly used. Blaster stated mixing a 3:1 ( RB:WW ) ratio will bring out the Willy Wonka in you.

Neutral White (NW) - The preferred white color. A much more natural color that brings out warmer colors in coral. Best matched with RB in a 2:1 RB:NW ratio provided you are using NW LEDs that can do 180 lumens at 700mA (the Chinese variants usually cannot).

Cool White (CW) - Very bright and efficient but dull in warmer colors. Replaced by NW as the preferred white LED. Some users have reported better color when using both CW and NW in an array while othes say NW+RB can achieve the same color output. There is a wide variation in the color tempurature of different bins of LEDS. The DX bin of Crees and most Chinese LEDs are typically cooler (more blue) in the 6000K - 10000K range. Cree XP-G are more blue than Cree XR-E.

Cool Blue (aka Blue, aka Standard Blue) (CB or - On the greener/blue side. These bring out the colors the neutral white and royal blues wont [what colors?]. Can easily overpower other leds leading to a 'windex' look. Blends well with NW and RB, consider runnning without optics to blend better.

Royal Blue (RB) - A must have. When your working with cool white or neutral white is the go-to blue.

Cyan - VERY green unless you are able to choose your exact binning. They can bring some wicked colors out but leave an awful green shadow everywhere. Even when clustered closely I would not recommend these to the average DIYer.

Red ( R ) - Very difficult to blend with other colors. Even a single red in a fixture can be distracting. Consider running reds on lower power (with a dimmer) and without optics. There is some debate that red wavelengths inhibit coral growth. Preference is to use NW leds to being out red colors.

True Violet (V or TV) - Litte impact of visual appearance, slight pop on certain colors, little or no purple added to overall color. Primary usage would be for growth. Use with caution (PAR meter preferably) since they put out more light than is visible. Difficult to source.

http://glassbox-design.com/wp-content/uplo...axspect-LED.jpg

This section could use more specifics (e.g. WW is typically 5000K - 6000K). Notes on specific bins. Links to individual emitters

Recommended Ratio

4 NW : 7 RB : 1 CB

NW: Cree XP-G NW. Use NW LEDs that can output 180 lumens at 700mA (the Chinese variants usually cannot).
RB: Cree XP-E RB
CB: Cree XP-E Blue

Shimmer
Shimmer is the moving bright lines (and corresponding though less noticeable dark areas) on the tank inhabitants and substrate. You also see the same shimmer on the bottom of outdoor pool or the shallow water at the beach. Shimmer is caused by turbulence at the water surface concentrating the light emitted by a point source as it is refracted towards the bottom of the tank. Shimmer sometimes also includes the light reflected directly back at the viewer off the water surface.

Compact fluorescent bulbs (PC, VHO, T5) produce very little shimmer because the light comes from a very large area (the entire surface area of the bulb). Metal halides produce a mild shimmer since the light comes from a single concentrated point. LED fixtures produce a lot of shimmer because each LED causes its own shimmer lines though each shimmer line is smaller than MH. MH is typically considered the standard for pleasing shimmer probably because it resembles the sun (a point source). LEDs have an additional problem when a fixture combines LED with different colors - each shimmer line is of a different color. This is "disco ball" effect.

Options for minimizing LED shimmer:
- Reduce surface turbulence (reduce flow, orient flow away from the surface)
- Hang the fixture close to the water (< 5") with no optics
- Hang the fixure really high (3-5 feet) and use tight optics (20 - 40 degree)


Color Blending (Color Shadows, Color Separation)
LED fixtures using several color LEDs often cause color shadows. This appears as shadows in the tank of different colors. It occurs when one LED illuminates the shadow cast by a different color LED. The resulting shadow looks like it has a color cast compared to other shadows nearby. It is most noticeable on the sand bed. Related is color separation where turbulence on the water surface refracts each LED slightly differently. This results in moving areas of slightly different color. Again most noticeable in areas of uniform color such as the sand bed.

Options to improve blending:
- Cluster LEDs as close as possible (even touching).
- Hang the fixture close to the water (< 5") with no optics
- Hang the fixure really high (3-5 feet) and use tight optics (20 - 40 degree)
- Use diamond diffuser in front of the leds. This is similar to the diffuser used in flourescent office light fixtures. Available from Home Depot. Link?

Spotlighting
This is when the tank is unevenly lit (like a spotlight on stage). It is caused by fixtures close to the tank with tight optics or excessive spacing. Any specific/concrete guidelines?

I would love to see a wiki type feature on nano-reef so others can update this with corrections and new information. I don't think we do. Instead I'd encourage everyone to post any changes. This includes changes to make the text clearer, more concise, correction, specifics, elaboration, removing old information, adding new information. Please post the exact text you want. Newbies can be refered here ulimately helping us all so they can spend their time experimenting rather than reading.

 

the above is something i ran across on another website.

Anyway, I would deffinitely go with a heatsink vs some low mass aluminum U channel. Heat will deteriate the LED; as described and charted on the cree data/cut sheets. It boils down to when you over build something, you will never know it; but when you under builld, you will always find out. Heat sinks can be any shape that easily accomodate your tank set up and get the LEDs where you want them.

I would go with no fewer than 48 LEDs if you are planing on SPS. Otherwise, 36 would be fine for Softies.

As for lenses, 60 degree would be just fine. Lenses make a huge difference in par dirrected toward the tank/corals, versus no lens at all. there have been several examples showing this. Any lens, 40 to 90 degree will make your fixture more efficient. IF you are curious about the delivery of the light, get some paper and a protractor and draw it out so you can see the angles.

Color of your LEDs/tank is completely a personal opinion. Lots of people like the bluer look (a ratio of two blues to one white). I built my lights with two whites and one blue. I like a whiter, more natural look... that is just me. However, i think i would do a one to one ratio of blues and whites next time.

It all boils down to what your objective is. Coral type, Color rendering, and what works for your physical set up, and budget.

andy

 

the above is something i ran across on another website.

Anyway, I would deffinitely go with a heatsink vs some low mass aluminum U channel. Heat will deteriate the LED; as described and charted on the cree data/cut sheets. It boils down to when you over build something, you will never know it; but when you under builld, you will always find out. Heat sinks can be any shape that easily accomodate your tank set up and get the LEDs where you want them.

I would go with no fewer than 48 LEDs if you are planing on SPS. Otherwise, 36 would be fine for Softies.

As for lenses, 60 degree would be just fine. Lenses make a huge difference in par dirrected toward the tank/corals, versus no lens at all. there have been several examples showing this. Any lens, 40 to 90 degree will make your fixture more efficient. IF you are curious about the delivery of the light, get some paper and a protractor and draw it out so you can see the angles.

Color of your LEDs/tank is completely a personal opinion. Lots of people like the bluer look (a ratio of two blues to one white). I built my lights with two whites and one blue. I like a whiter, more natural look... that is just me. However, i think i would do a one to one ratio of blues and whites next time.

It all boils down to what your objective is. Coral type, Color rendering, and what works for your physical set up, and budget.

andy