Yes, I am starting to think that way as well about the Co2.
I have planted crypts, anubias nana, rotala, dwarf sag, swords, ludwegia repens (excuse the spelling), so all low light plants, and to be honest, they are looking really healthy and have grown in the 2 weeks that they have been planted.
I guess I just like the idea of a high tech tank, they always look so lush and beautiful.
I think I might get a new set of the standard tubes, I havent replaced them for a couple of years.
On looking at them, they are the combo ones - 'Tropical' which is a mix of white and pink. Maybe the plain sunlight ones would be better?