250 watt what? Halogen work light?
fluorescents aren't a must, they just work well for veg for the price. I veg my mother plants under a 250 watt HPS.
You can use either MH or HPS for your whole grow.. MH in flower will produce fluffier bud, but you will have more trichomes because of the added UVB in the spectrum. HPS is the trusted standard to produce big hard nugs, but they make plants a little stretchy in veg..