i would strongly advice against buying that light. its not made for growing, its not going to produce the right spectrum and it will be too hot. if i were you i could do either t5 floros or cfls(you can get 42watts at homedepot 2 for like $3). you wont get the best density in your buds and it wont be the most bud you can get from a plant. but you can def grow some quality weed and if you had 2 rooms or felt like seperating your current grow room, you can easily do a perpetual harvest. just look at the growfaq or in the grow room setups or one of filthyfletchs DIY things, and just make it on a smaller scale.
alright man thanks. What do you estimate the yield might be.the cheapest 400watt hps grow light i know of is High Tech Garden Supply . pretty much the staple of any budget flowering room light. i use one and my only complaint thus far is that i wish i got a 600watt. id say its overkill for a 1 plant grow. i wouldnt grow any less than 6 plants with this.