DIY lighting question

[nickbuter]

When making a DIY lighting, I assume you don't measure the watts per gallon in the output, just the actual wattage used in a fluorscent light. Correct? What importance do the lumens have? Or is the spectrum the most important thing when deciding what lights to use? Or should I just stop being so cheap and go buy something designed for this application?

 

[Notophthalmus]

I'm sure someone else can explain this better than I, but the amount of Photosynthetically Active Radiation is the most important thing; this is a function of spectrum and lumens. Wattage is just used as a shorthand for lumen output, based on T8 or T12 fluorescents. Other types of lighting have very different light outputs per watt; incandescents put out a lot of light as IR, so their PAR/watt is low. T5 fluoros and metal halides may have higher PAR/watt.

 

[WinnipegDragon]

Check Rex Grigg's site. He suggest using LSI or Lumens per Square Inch as a better indicator than WPG, and I tend to agree.

My 2 x 24w T5HO setup is 8000 lumens, which is equivalent to over 100w of CF for instance.