Originally Posted by Cich-Oh

I was sold a dual 40w satellite with an actinic blub for 170 dollars at the LFS. After researching my buy, I'm finding that this is a light for reef aquariums. Did they rip me off? I will it definitely help me grow any species of plant?

Originally Posted by Llama

Green plants need mostly red.

Originally Posted by mathas

According to the Current website, which is what I assume you mean by "dual 40W satellite", the actinic bulb in your fixture is a dual 420/460nm actinic bulb. There are better bulbs available, but it's not entirely wasted. See my response to Llama below for further info.


I disagree, at least with the word "mostly". They certainly do need light in the red wavelengths, but they also need blue light as well. According to Universität Hamburg's biology department (and other sources, but this is the graphic I have bookmarked), both chlorophyll a and b molecules absorb specific wavelength blue light even more strongly than they do red: http://www.biologie.uni-hamburg.de/b-online/e24/3.htm. This will, of course, likely vary a bit from species to species, but it's a good overall guideline.

Given that, the ideal bulb (or bulb combination) for a planted tank would have strong output in both the 430-450nm blue range, and the 640-660nm red range. The actinic bulb Cich-Oh has does fairly well at the 430-450 part (see the spectral power distribution graph on Current's SunPaq PDF sales guide), but it obviously does nothing for the reds that plants need.

Originally Posted by Cich-Oh

so you're saying they're a good combination to grow nearly anything? like hairgrass? thanks so much for all your useful info!