Many growers veg entirely with CFL's because they are cool and you can get them within an inch of the plant top. The idea is to have a short, sturdy main stem; the less stretching the better. MH lights are relatively hot and you have to take great care to keep a steady air flow over the bulb and plant canopy, especially with young plants.

I'm currently mixing a 400w HPS, 250w MH, and several CFL's during flowering. I vegged entirely with CFL's, but I'll probably add MH for my next veg.

25 gallon tub? Wouldn't that fuck up his doctor's office look?