The adventure of the 125gal tank

[kien]

Originally Posted by Fishgirl

what does it mean by it offers 420/460nm, 700+ nm not sure what those numbers mean or what nm stands for????

Bulbs come in different wavelengths of light. If you look on the box for a T5 light it will typically show you a graph of the light spectrum from blue to yellow/red. That bulb will output light somewhere on that chart and that is its output wavelength.



Actinic lights, for example, produce only light at a specific wavelength--420 or 460 nm (nm stands for nano meters - the measure of wave length). This peak wavelength value, which produces a very blue light, was chosen because during photosynthesis chlorophyll a absorbs light near this wavelength. These blue lights also help to augment the fluorescence of corals. That is, it makes them glow