Conventional wisdom on actinic blues

[aquanoob]

I've seen a number of posts suggesting that actinic blue lights are useless for freshwater planted tanks... but am wondering if there is empirical evidence that suggests this or is it just because it seems right.

Basically I'm wondering because chlorophyll A absorbs 662nm light(red) and 430nm light(blue-violet). Chlorophyll B absorbs 642nm light (red) and 453nm light(blue). In both cases the blue absorption rate is much higher. Really those are are broad absorption bands, with peaks at the numbers I listed.

Looking at the output for one actinic blue(http://www.bestgrowlights.com/site/403863/page/436991) it seems that this light should be close to ideal for plants.

The red band is important also, so lighting only with actinics seems like a bad idea... but characterizing them doesn't mesh with the science as I understand it.

so is there something I'm missing?

EDIT: btw, I'm just getting started with planted tanks... so I'm not in a position where I want to actually start messing with weird light set ups, this is more academic curiosity.

 

[krap101]

i think someone said actinics make their plants grow thicker?

 

[greenmaji]

travis simonson asked a plant expert about this and got a scientific responce and has posted it once from what I remember..
It isnt that the antinc light does nothing for freshwater plant growth but by adding it alone it does very little for freshwater plant growth.

 

[greenmaji]

I found the tread!!!
http://www.aquariumadvice.com/viewtopic.php?t=54048&highlight=light*

 

[malkore]

actinics will promote bushier growth in plants, assuming all other parametters are good.
but actinics alone don't provide the full spectrum that plants need.