Well my bulbs are being given to me free from the charity in my sig so i will not be complaining no matter what they are, but at some point when im setting up a high tech tank, i want the "Best Bulbs i can get".The more I learn about lights and the spectra and color temperature of bulbs, the more I believe that you can chose the bulbs you want based on what looks best to you. I don't doubt that there are some differences in growth rate for different bulbs, but I doubt that the differences are very great. And, color temperature seems to be very little more than a marketing technique.
In a perfect world where I had all the money i needed i would, but to be honest i couldn't even afford the bulbs i am getting a charity is providing them to me free of charge along with a plant package.Giesmann name is well known to me they are one of the most recommended bulbs in the SW end of our hobby, well know for quality but it comes with a quality price tag.Lighting outside the visible spectrum doesnt do much for plants. As a matter of fact, infra-red will actually slow down photosynthesis and too much will inhibit it.
Bulbs come with all different spectral outputs and the intensity of the spikes can vary widely. Look for bulbs that come with a spectral output graph/curve and secondly look for the ones that quantify the output (Y-axis) in a term such as watts/per lumen/nanometer or Watts/nanometer per 1000 lumens NOT just relative intensity. Relative intensity means they take the highest peak in the graph and call this 100%; everything else is relative to that (i.e. 1/2 the height would be 50% and so on).
OhioPlant, that graph is typical curve for a plant called anacharis. I havent gotten to the botton of why this particular plants action spectrum is typically used. Here is a few more gifs to digest:
This bottom gif is from a University study (cant remember which one) that was featured in a Journal of Plant Physiology article on photosynthesis. It shows a steep drop off after 453nm for chlorophyll b and the same for chlorophyll a after 662nm. This is why 460nm actinic usually dont work well and also why the far red doesnt either.
The only bulb I have run across that is largely red light is the incandescent light bulb:
If you have T5HO lighting why not use the Giesmann 6000K Midday:
Or the AquaMedic Planta bulb:
Both are very popular.