And costs 50% more electricity to run than a 250w hps...

The cost is only a few dollars more but the benefit to your plants is great.

You don't even know what size grow area he's got !!!!!!

Maybe I'm stoned but that is soo funny! Dude, what are you trying to imply, the cost to run a bulb costs more in a larger room than a smaller room? Or that the added lumens over the 250 watt would not be a welcome addition and a benefit to the plants, regardless of the size of the room?

My space is 3x2-1/2x4-1/2 and another 8 inches between the joists. But the light will need to hang down therefore the 8 inches are pretty much wasted and maybe even lose some of the 4-1/2 also. There is enough room for me to get in plus some additional space behind me beneath the first landing and 3 steps, about 2h x 5 x 4, storage for the most part.

Do you adjust the height as you go with HPS lamps like you must with Flourescents?

What's the deal with fans? Thinking of using a inline 4in fan to vent through a carbon scrubber (got the stuff to make one as per instructions found here on rollitup!) into an adjancent room.

You guys are good!

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Gimme some of 'dat, home sweet home grown.

Yes you adjust the height as you go just like floros.