Just my personal experience, but with my lower light, no CO2 tanks, I have had better luck with t5no's. I have two Aqueon t5no fixtures over my 28 gallon tank. It is an odd shaped tank, and I have two 24" fixtures, for a total of four 14 watt bulbs with 56 watts total. I space the two fixtures a few inches apart, with one fixture at the front and one at the rear. They are resting directly on the rim of the tank, with a glass canopy. These fixtures are very small and lightweight.
I also have a stock sized 29 gallon (30" long), with a t5ho light fixture on it (dual bulb), so a total of 48 watts. I have had to diffuse the intensity of the light to prevent algae.
I use Excel daily, and dose with Flourish Comprehensive at a half dose, once per week. Dosing would depend on your fish load.
I hope this helps.