Totally incredible light!!! Venture 775w p-start
Notice that the spectrum is exactly like natural sunlight.
I bought a couple of lamps, and the ballast from businesslights.com - because this is a "commercial" lamp for industrial use, the price tag is $80 for the 775w lamp, and 100$ for the ballast with no case. If this was a "hydroponics" "horticulture" lamp, the price would be easily $120 or more for the lamp. I measure light intensity using the PAR method (photosynthetic active radiation) and at 2 feet from the lamp the PAR is 1100 (micromole photons/square meter/second. This level of light is completely insanely high, which I suspected, from looking at the lamp specs. The lamp is spec'd in lumens, which does not give the real measure of PAR (lumens is the retina sensitivity, and PAR is the plant sensitivity). For a comparison, I ran a 600W HPS lamp, and at 2 feet the PAR is around 600 - this Venture pulse start metal halide is a killer of a lamp!!! When you look at the spectrum it is very rich with blue, and red, that plants love, plus it gives the full spectrum, which we know from lermer's posts, is essential. The difference is that lermer is pushing a CMH which only goes up to 400W, and is no way comparable to this pulse start lamp. Also, venture makes the pulse start in a large selection of watts, including a totally killer 450W lamp.
The pulse start is a new technology where the lamp life is far longer, because there is no "probe start" parts to go black and wear out - it just ignites with a high voltage spike that vaporizes the mercury, and then all of the halides vaporize and form a plasma, which is using all of the expensive rare earth that you can imagine. The arc tube is completely optimized for maximum photons/watt, and is totally different from the shape of the probe start arc tube (regular metal halide, that is not even as good as just and HPS, which just gives pure yellow/orange light, that chlorophyll cannot even use - that plant has to use intermediate carrotenoids, which is nowhere near as effective as stimulating the chlorophyll directly.
So right now, I have 8 x Black Krim tomato plants under this light, and they are just right now starting to go into bloom. This Black Krim tomato comes from the Crimea/Black Sea region, and it loves light! Also, I am going to grow Biggie Chile, which is a fantastic hybrid Sajuaro Annaheim pepper.
I have a 3 feet x 9 foot garden area, and I expect a fantastic harvest. This set of 2 lamps would be large enough to power a 5foot x 9 foot garden, but that is going extreme! I am running 775w x 2, each has a really nice lumenmax reflector, which is also quite reasonable from horticulturesource dot com.
Here is a link that might be useful: Look at this venture lighting data sheet