Sal and Dogs. What kind of Light intensity levels are you running? PAD manual has everything listed in watts per sqmeter based on canopy depth. For my little 14-18" plants I'd assume around 200w per sqmeter going by the manual. Is this based on LED lumens per watt? What about HPS and halogens? Is there another way to calculate this: Chlorophyll Absorbance Spectra CAS, Action Spectra for Photosynthesis ASP, Quantum Yield Curve, PPF, PPFD? Just trying to find the best way to setup my LED wannabe Fluoro tubes. I find the PAD manual a little vague in this area. Total combined input watts versus actual light intensity varies in a huge way even between different LED's. I assume Rauber must use a meter to actually calculate this but doesn't specify the scale that he uses. I know, I know experimentation but like most humans I'm inherently lazy and hate to repeat work that has already been done, especially by someone smarter than myself.:upsidedow