Slow Growth and Pale Green leaves

[jibsonline]

Hi,

I'm kind of totally new to aquatic plants. But I do have plants in my aquarium for a while. My plants never die. But the problem is that the growth is slow and the leaves are not dark green.

I have a 50 Gallon(3 * 1 1/2 * 1 1/2 feet) tank. The lighting is of 36w CFL * 4 nos, I have substrate contro soil. I am attaching few images. Please tell me what is wrong.

[driftw00d]

No CO2 injection?? It makes a whole world of difference between with and without it. Invest in a system if you haven't got one.

[jibsonline]

I have DIY CO2 system based on sugar and dry yeast.

Can someone tell me how much light is needed per gallon. Mine is a 50 gallon tank and I have 4 lights of 2900 lumen each...