No one mention anything about your lighting. Keep it basic. There are tanks out there with just the basic water change and they are still amazing.

If you have a standard 120 4x2x2, I think your 150w halides are a little on the weak side. And kelvin of the bulb makes a big difference in color.

can you place a picture?

if the tank is running good and you have colors but doll as you say, try to use amino acids.....i did it with brightwell and in 2 weeks got amazing results.