I have done much research online into determining the ideal spectrum for growing algae. My goal is to custom-tune an LED fixture for maximum algae growth and maximum filtration capacity. So far, I have not been able to verify whether Algae best utilizes the Chlorophyll A or B spectrums, or a combination of both.

I build algae scrubber for freshwater and marine aquariums. The algae is grown on a vertical substrate with the system water constantly cascading over it, and illuminated on both sides. So far, the vast majority of people grow the algae with low-kelvin (2700-3500K) CFL or T5HO with great success. LED builds have been all over the board, but some evidence suggest that algae (at least, marine algae) responds best to 660nm "deep red". Thus the limited data would seem to indicate that marine algae (green hair algae, in specific) absorbs mainly the Chlorophyll "A" specturn.

Adversely, the horticulture industry reports that plants respond much better to the equivalent wattage (input) of 630nm. Growth of plants under 630s far exceeds growth under 660s. The theoretical explanation is that 630nm LEDs output 3x the power of 660nm LEDs, and that the difference is mainly the result of intensity trumping spectrum.

The "A" finding is also compounded by the apparent total lack of algae growth under warm white LEDs supplemented with 455/460nm LEDs ("B" peak in Blue). The lack of correct red component may be partially to blame, so this is only anecdotal.

I am currently preparing to run an experiment with 2 separate fixtures, one tuned to the "A" spectrum, and another tuned to the "B" spectrum. The experiment will be performed on 2 separate uninhabited saltwater system with fertilizer mixed in the water, essentially creating waste water or runoff water.

I would greatly appreciate any insight from anyone who has attempted to grow algae using artificial LED light. I posted a similar request on Oilgae and got zippo for response.

in LED