you will do better with this LED bulb that is 10 watts than a 70 watt HPS.....LED's make no heat and provide more usable light for photosynthesis than any other lighting source

High Power Hydroponic PAR38 42 LED Grow Light 85 - 260V - eBay (item 390162816610 end time Feb-28-10 21:38:05 PST)

any HPS bulb under 250w is not designed for horticultural use..it lacks the spectrums needed!

i would not waste my money on small HPS bulbs not designed for growing....waste of energy also!
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