I have a 90 gallon tank that I would like to add LED lighting to. I have used Hoppy's spreadsheet that I modified to calculate my lighting needs. See attached PDF file.
For my tank, I need 36 Cree XP-G2 LEDs running at 1 amp drive current. I have attached the spectrum of the XP-Gs LED by themselves. Do I need to add deep red (660 nm) to aid in photosynthesis? Per the spectrum attached, I would need 12 Deep Red LEDs at 560 mW each. This spectrum more closely matches the absorption of Chlorophyll a,b. What about adding Hyper Violet at 430 nm to get the Chlorophyll a spike?
I have not seen much data using anything but straight cool white LEDs for planted lighting. If they did add colored LEDs, it was only a couple, not the 3:1 ratio of CW to deep red that I am looking at.
I guess in a technical sense you have 2 semi-opposing positions:
1) excellent plant growth via a targeted spectrum of specific colored LEDS vs
2)an esthetically pleasing looking tank.
from a plant perspective your red to blue should be like 6:1
from an esthetic point of view well any color from 8000-6000K
(arguable and if taken to the color tone extremes 10000K to 3000K).
Created by adding all sorts of color combinations or just picking one LED
So you just need to compromise either way..
As to violet that is also a choice..
Ideally you could run a purple/pumpkin orange/ High growth/high par lighting and then switch to a color neutral lighting during "viewing hours"... but few actually bother w/ going to this extreme..
Speaking about extremes from the coral world..