LED Lighting question

[kwdelre]

I am trying to rig up a LED lighting system for my Saltwater Reef Tank. I need to achieve about 300 lumens at a distance of 2 feet. I am having trouble doing this.

Here is my question. I have 12 LEDs lighting up and producing approx. 300 lumens at a distance of 6 inches. What can I do to increase this distance? Would adding more lights increase my lumens distance? Thanks everyone.

 

[Resqueline]

Lumens is a distance-free unit. It's the total output from the light source (summed in all directions).
Candela, or Lux are the terms used for illumination of a surface (at a distance from the light source).
To answer your first question: use reflectors or optics.
To answer your second question: yes.

 

[kwdelre]

Thanks for the reply.....

I seemed to have misunderstood my requirements. I am trying to acheive a high PAR reading from these LEDs. Since PAR decreases over distance, would adding more and more lights increase this PAR reading?

 

[Resqueline]

As long as the LED's have photosynthetic active wavelengths at all then I assume that doubling the number of LED's will double the PAR reading - as well as the lux reading of course.

 

[mrdoodad]

LED Selection Solution

Preface note: If you are trying to duplicate sunlight, you want to keep wavelength in mind when selecting LEDs. Use a couple of 10mm, 5,000 MCD? Giant Bright White LEDs from Electronic Goldmine (goldmine-elec dot com), pt# G14040, maybe use with diffuser filters since they are blinding to look at (be careful!, these are brighter than a halogen source), and will turn night into day. I'm using some of these to light up business signs (only two required!!). These run on 3.4 vdc @100 mA each typically.

DD

 

[amdNRA]

Check this out and see if it would work. I just ordered this light myself (for a bike); but it seems like it can work in your application. It's got pretty good light output . More than likely, you would want to use a power supply at home.Hope that helps, Gil.

 

[amdNRA]

Sorry; the copy/paste didn't take.
Here it is: doubleudoubleudoubleu(dot)dealextreme(dot)com/details.dx/sku.25149

 

[amdNRA]

Had to spell out the website...Wouldn't take it otherwise...oh well