steveoutlaw January 3, 2011 January 3, 2011 I got one of the DIY LED systems from Robert Chu and I couldn't be happier with the colors and growth out of my corals. My only complaint with the fixture is that it is in a 12" x 12" array and my tank is 36" x 36" so some of the SPS are getting light on the top and the sides facing the inside of the tank, but not the sides facing the outside of the tank. This has caused them to lose some of their color on the areas not receiving direct light. Is it better to have the LEDs spread out more so that all sides of the coral are receiving direct light? I've seen fixtures like this and it seems like they provide better light to the whole coral.
dakotasreef January 3, 2011 January 3, 2011 I would think that your fixture would work just like a halide pendant. Corals underneath the pendant will get great light, but the ones near the edges will suffer. Are you using optics? If so, i would think that would limit the amount of light to the edges. With that size fixture it seems like the outer edges might suffer. I have not used leds as a main light source, so I am no expert.
ErikS January 3, 2011 January 3, 2011 .......Are you using optics? My first thought, what are the optics? You might be able to swap them out from a larger angle, if say they're 40* you might try 70*.
Jim January 3, 2011 January 3, 2011 Steve, I have a fixture from Robert that is over my 30x30 cube. It is 36 LED's on 6 24" aluminum rails. Does a pretty great job of spreading the light and keeping the intensity high enough to grow SPS. Might be something to consider. Obviously it would involve taking your current fixture apart. Jim
bankyf January 3, 2011 January 3, 2011 LED's are much more directional(point source light) than halides or t-5's. It would help most fixture significantly if there was a way to angle some of the leds so there was more reflection off the glass and more light bouncing around. Wide optic lenses may help this a bit.
steveoutlaw January 3, 2011 Author January 3, 2011 Thanks for the responses. I saw the fixture on the aluminum bars, but I'm not sure I want to go that bulky......I was just wondering if putting the LEDs a little further apart, say on a 24" x 24" heatsink would do better. The entire sandbed of my tank gets light, but the edges of the tank higher up do not get the light. Spreading them apart may also help with reflecting off the glass and getting light to the whole SPS at the higher levels in the tank. How do you tell what optics you have? They are the 3w Cree LEDs and I believe they are the 30 degree optics.
Coral Hind January 3, 2011 January 3, 2011 I think going to a 24" x 24" heat sink is the great idea. It would spread the light out alot more. You could also add some more lights to it if you want.
dakotasreef January 3, 2011 January 3, 2011 If they are 30 degree that might be the problem. I might try some 65 to 70 degree optics. I think you would see a huge improvement. I also think spreading them out with some extra leds can't hurt either.
davidm January 3, 2011 January 3, 2011 OK< I'm ignorant but interested - how can I find out about the "DIY LED systems from Robert Chu"? I'm not crazy about the costs of the AI, but I'm also not crazy about all the soldering for a DIY project - so I'm hoping this is a good option/compromise.
BowieReefer84 January 3, 2011 January 3, 2011 (edited) OK< I'm ignorant but interested - how can I find out about the "DIY LED systems from Robert Chu"? I'm not crazy about the costs of the AI, but I'm also not crazy about all the soldering for a DIY project - so I'm hoping this is a good option/compromise. Another option is the drilled tapped heatsinks and solderless conections from rapidled.com. I used one of their diy kits, and completed the entire build with NO soldering. Very happy with results. The only thing I would change may be going dimmable (not for controlling sunrise/sunset, but to get color temp right). I know the AI cost way to much. Not sure about Robert Chu prices. Edit- In reference to your question Steve it sounds like there is a large gap between the led perimeter and the tank perimeter. I have 24 leds over a 29 gal biocube (perhaps overkill) I think you want to get them spaced 2-3 inches between led's, and closer to the edge of the tank. 24x24 would probably be good. If you have corals really close to the glass you may even want it like 30x30 based on what optics you are using. Edited January 3, 2011 by BowieReefer84
steveoutlaw January 3, 2011 Author January 3, 2011 Thanks Chip.......that's just what I needed. Ok, so where do I find a 24x24 heat sink?
Coral Hind January 3, 2011 January 3, 2011 OK< I'm ignorant but interested - how can I find out about the "DIY LED systems from Robert Chu"? I'm not crazy about the costs of the AI, but I'm also not crazy about all the soldering for a DIY project - so I'm hoping this is a good option/compromise. Robert Chu is known here and other reef boards as "chucelli". Here are some threads of his. http://www.wamas.org/forums/topic/34322-led-pendent-gen2/page__p__295882__fromsearch__1&?do=findComment&comment=295882 http://www.wamas.org/forums/topic/35740-inline-led-design/page__p__307460__fromsearch__1&?do=findComment&comment=307460 http://www.wamas.org/forums/topic/33691-high-powered-led-pendent/page__p__290706__fromsearch__1&?do=findComment&comment=290706 His page at reefaddicts.com http://www.reefaddicts.com/content.php/70-LED-pendent-build
Guest thefishman65 January 3, 2011 January 3, 2011 If it works with your mounting scheme and heat dissipation using L or U channel from home depot maybe cheaper.
steveoutlaw January 3, 2011 Author January 3, 2011 Rapidled.com sells drilled and tapped heatsinks All I could find was 6" wide....I'd have to bolt 4 of them together and it would cost me $200. I may just consider the U channel.
Guest thefishman65 January 3, 2011 January 3, 2011 What current are you running the LEDs? Do you currently use a fan?
steveoutlaw January 3, 2011 Author January 3, 2011 What current are you running the LEDs? Do you currently use a fan? Ok, I bought them and plugged them in and they worked......that's about all I know. It currently has an aluminum heat sink with a 6" fan on top of it. Everything about the fixture is cool to the touch.....even the LEDs themselves.
steveoutlaw January 4, 2011 Author January 4, 2011 Not sure.....all the ballast stuff was put in a single box and wired very neatly. I'm actually very impressed with the quality.
flowerseller January 4, 2011 January 4, 2011 Steve, if you stretch all the LED's you have now on the 12" to 24" won't it lower the output per square inch?
Guest thefishman65 January 4, 2011 January 4, 2011 How many LEDs (or did I miss this)? It might make more sense just to add more at the edges.
ErikS January 4, 2011 January 4, 2011 How many LEDs (or did I miss this)? It might make more sense just to add more at the edges. Yep, if you spread them out you'll need to add more. I would figure chucelli can help, after all he built it (and after all he & thefishman65 are yel olde veterans of the RC DIY LED thread - arguably the best source of LED information)
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