i was thinking about getting one but dont no if it would fit..Male sure you get a 400w cooltube HPS when you can afford it and use it start to finish. For now make sure the cfls are direct overhead to aviod the short node branching, make sure temps are under 80. The hps will grow the branches much quicker and thicker than cfls and will give you 10x better buds.
so wat size 400w would fit in ther?A 400 would fit. There are people here that have smaller and run them. But if that's not the way you want to go. Get a T5. One that will cover the whole top. Maybe a 2" 6bulb. It will give you denser buds over the cfl.