I have a science Question?

I am wanting to know what is the lighting factor that you really need in order to keep coral and algae alive? Lighting factor being watt, lumens, candle power, amps, etc.... I hope the question is clear.
The reason I ask is I am pretty limited on space to get more lighting where I need it. There are options but I dont like them. So if you know the answer to my question it may help find some different lighting options.
Science geeks please jump it.;D
Oh and if you have an answer maybe why would be useful. Like if you think the answer is watts, why?
As always thanks for the help guys/gals

 

If you feel like reading this article has some pretty good information and may answer your questions. Even though the author is trying to sell you lighting the information is correct.

Aquarium Lighting; Kelvin, Nanometers, PAR, Bulb, Watt, MH, LED, light basics.

 

the answer to your particular question boils down particularly to PAR... If you can produce a PAR that has consistent levels in all wavelengths (6500k) then the growth will be fast. Your photosystems will have a limit as to how many miromoles/m^2/s they can absorb (called photoinhibition) but typically, levels of 600 PAR (micromoles/m^2/second) and below can be tolerated before photoinhibiton is reached

in layman terms, you want the most efficient type of light. for coral, there is a trade off... viewing pleasure vs. efficiency of photosynthesis. If you want fast growth go with 6500k. if you want beautiful colors and lesser growth, go with 20k... anywhere in between is a mix of growth and color based on how high the kelvin is.
For algae, you will want to go with 6500k so it is the most efficient in its photochemical processes

 

Great answer
+K

 

indeed. that was very well put.