Spread of individual led diodes

[Acroporaaddict]

I'm making a custom t5/ led hybrid. It will be running 8 39w t5 bulbs and have two rows of led. The leds will be royal blue and uv, they will be mounted with screws for easy replacement if they burn out. The fixture is roughly 35" long. My question is how many leds should I use for each of the 35" strips? What is the coverage of a single led diode? I was thinking: RB UV RB UV RB UV RB UV RB UV RB. That should allow roughly 3" spacing between diodes and each strip to be ran off a single power supply. Does that sound about right?

 

[theatrus]

Spread can vary by diode, but the majority of silicone domed diodes have spreads commonly stated as 120degrees, but the peaks may be variable.

For a supplement, 3" sounds totally reasonable. You'd be hard pressed to pack them closer if you're using star board LEDs.