I cant really analize these charts for a couple of reasons, one I am unfamilliar with the method used to determine "photosyntetic efficiency (PUR)" or what sampling criteria was used to determine this. Two: it is hard for me to analize this because I have no idea where the numbers came from. I have worked in the engineering field for 7 years now and I see weird charts like this all the time and if I cant get the sampling criteria and test methods defined readily I have found results to be inconclusive.

I still see lm/w is much higher on HPS

Anyone with expierence growing under both?? I always see floros with good numbers but anyone that uses them switches back to HID (thats just what I keep running into). Is there anyone out there who E-bayed their HID's when they got a hold of some triphosphor T8s with electronic ballasts?

Its probably somewhat accurate, you sound like a smart guy and all. In fact, what do you think of digital ballasts compaired to normal ones for HPS and is their a hands down winner out there as far as brand names go or are they all pretty close like the non-digital ballasts?

If you get a chance, please check out my thread in this section about CO2 if you could.

To clarify on the LEDs, I read on a gardening site a study that concluded that that spectrum of light was barely present in natural light but when certain plants were exposed to it they became mostly female. I figured what can it hurt? The 2 watts the bulb uses isnt going to even show up on my bill.. haha