what are best spectrum colours for algae growth

[yanton]

can anyone advise on the ultimate colour mix for algae growth.
is it blue and red mix?

[Floyd R Turbo]

For LEDs I'm assuming is what you are asking about

660nm Deep Red
440-450nm Royal Blue

Ratio Red:Blue generally in the range of 5:1 to 8:1. Most people (including myself) have taken that figure to be a ratio of the LEDs but it is actually more likely to be a ratio of radiometric power. Since blues LEDs are inherently more powerful in that respect (at the same drive amperage), you may actually need fewer blues, or at least run them at lower power. I figure that blues are about ~50% more powerful than reds so you could stretch the red:blue LED ratio to 10:1 and probably be good.

[Nick28]

Has anyone experimented with the feit electric blue bulb?39983999

it appears to just be a bulb painted blue but it gives off what seems to be an intense blue and violet area hitting both chlorophyll A and B peaks nicely.