That tank is 16 inches high, so a single T8 bulb gives about 15 micromols of PAR at the substrate, and it takes about 30 micromols for low light plants to do well. With your two bulbs you should have enough light - about 30 micromols. The color temperature of the bulbs is your personal choice - whatever makes the tank look like you want it to look. Most people don't use 12 hour photoperiods. That can lead to algae. Most of us, I think, use 8-10 hours.