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				 DIY LED help 
 I'm having a hard time understanding how to decide the number of LEDs needed for a diy fixture.  There are lots of formulas floating around for it but it seems most people end up dimming their fixtures way down around 50% which leads me to believe they could have gotten away with less LEDs.
 From what I gather the formula for figuring out the light spread is tan(degrees)*distance.  When I do the math the diameter of the beam is huge even with 80 degree optics. I found an online calculator that says with 80 degree optics the beam is 13.43" only 8" from the bulb and 33.6 at 20".  Does that seem correct?
 
				__________________72g bowfront, t5.
 29g JBJ nano cube, ATI 26HD.
 
 Livestock: clown fish, chromis, coral beauty.
 
 Corals: Toadstool, maze brain, candy cane, mushrooms (purple & green hairy), button polyps, green zoas, GSP.
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