Aquarium LED fixtures

[Ray]

Magnus - it is the chlorophylls that do not absorb the green, but there are other chemicals in the leaf structure that do, some of which pump energy directly into the photosynthesis process. That upper curve is a total absorption of all chemicals - i.e, their individual curves blended.

The "hump" in the LED output is a remnant of the phosphors used to produce white light. It's presence doesn't detract from the absorption (or the appearance, which was the goal), and adds a little, so I'm OK with it.

David - by the "original", I was referring to matching the blackbody spectrum. The don't do so, but come closer to doing so than the cheap bulbs we find at the hardware store.

I'll grant that the white LED light is not a necessary thing for the plants, but if you want to grow and look at your plants in a home environment, they do look a lot better than the red/blue combination. Ignoring that fact is folly.

[DavidCampen]

Originally Posted by Ray

...I'll grant that the white LED light is not a necessary thing for the plants, but if you want to grow and look at your plants in a home environment, they do look a lot better than the red/blue combination. Ignoring that fact is folly.

I quite agree, most people want white light not bluish-red and therein lies the crux of the matter - current technology white LEDs are no more efficient than T8 or T5 linear fluorescents in supplying light for photosynthesis. If you want to reduce electricity use over fluorescents by using LEDs then you need to use mostly deep red LEDs.