Hi everyone, i am just about to build a Vegetation box sized: 120cm X 80cm (4ft X 2ft 8i), for 6 plants during vegetation period. it looks like this: ==== l o o l l o o l l o o l l&= = Walls ==== O = Plants i usually use 2 X250watt CFLS 18,000 lumen each, total 36,000 lumen. they do alright, but not great. i want to switch to a Metal Halide 400w retrofit / hps ballast in a cooltube total 53,000 lumen i plan to keep the plants height small about 60cm / 2ft. My questions are: Will this 400w cover the floor space with as much light as the 2 CFLS?? The MH has more lumen than both of the CFLS combined, does that mean it will be better?? Is this space too big for a 400w MH for Veg?? Will a cool tube keep it cool enough? .