CFLs suck, only a small percentage does down to the cham, the rest bounces off the curls and everything else. You are better off getting a linear bulb that goes across the top of the tank.
We cant recomend a 5.0 or 10.0 till you you tell us your tank size, and if you are moving to a bigger one in a few months.
if its 2ft, a T8 5.0 is great
If its 3ft a T8 10.0 is great, if you have some plants
If its 4ft, a T5 HO 5.0/6% is great since it will penetrate 2ft down
If its over 5ft, you are better off with well planted and a T5 HO 10.0/12% as it will penetrate about 3.5 ft.
penetrate= 15uw/m2 which is the min for most chams.