Well if you're just changing the lighting system for sake of the look of the cover itself, that's fine, but be careful that you don't move yourself up into the "high-tech" lighting range without that being a "concious" move. The -amount- of light (eg. total wattage of the bulbs, regardless of color spectra) is like the gas peddle for the plants. Step on the gas too much and it gets more dangerous, just like cars, in the sense that a fast growing plant needs more "gas." That means extra systems for CO2, more fertilization etc. In your tank size, I'm pretty sure anything above 2 watts per US gallon would be considered "high lighting" and would get you into this area. Apologies.. as I may truely be forgetting.. in fact I almost think I vaguely remember that you might have taken some steps about this stuff(?) even CO2?
~~waterdrop~~