This is my very first grow, i used from start till a few days ago a 400 watt HPS grolux without any problems....within 5 weeks from seed i've grown 4 big ones (and 4 small ones due to my mistakes) into 2 footers grown in soil without any particular problems and almost no ferts.....now that i am into 3rd week of 12/12 i have added one more 400 watt HPS....i did some research and found this particular type of HPS which is called SHP-TS....that is designed especially for flowering....it is enahanced in orange and red spectrum....in other words does the same job with an MV/UVB lamp without having all the unpleasant side effects of using a UVB lamp (skin burns,loss of eyesight,skin cancer etc.).....as for growing veg. i came up to some new type of floros made by Sylvania...they're called GROLUX as well.....with four of those 4ft 44w each tubes you can cover an area of 12sqft only for veg....total of 176watts emitting the lumens of a 250 MH bulb....the total price for the floros is more than the MH but the operating cost is less,the distance from the plants is less, the heat emitted is less and the life of the bulbs is longer......