Hi gferreira, nice to see another Mexican member on this site !! Where do you live ?
I recently set up my second nano, it's a 10 gal, I put 3 15 watts 6,500 K screw in CF lamps over it and DIY Co2.Some algae issues yet, nothing to be scared, LOL.
I think your tank is over-lighted, 6,500 K bulbs are enough for plants (actinic is for reef tanks), with 10,000 you are flirting hard with algae issues, not to mention pressurized co2 is too much for a 6 gal also.So I second MrBelvedere's thoughts.If you still using that co2 method you will have to regulate it very well and pay close attention to Ph levels as well, specially because you will use RO/DI water.
For the photo period, if you let the 10,000 27 W bulb, you can begin with 8 hours per day and see what happens.
Carbon will do any good in the tanks either, it can adsorb some Azoo's substrate nutrients.I've read carbon is a big no no for planted tanks.
As for the initial planting, it's matter of tastes, in my 10 gal I began with Hetheranthera Zosterifolia (stargrass), Althernanthera Reineckii Rosaefolia, Hemianthus Callitrichoides "Cuba", Higrophylla Polysperma "Rosanervig", Hydrocotyla Verticillata and Cryptocorine balansae brown. Later I added some Ceratophyllum demersum and Limnophilla Sessiliflora (Ambulia) to fight the algae, and a friend of mine gave me some Ludwigia Arcuata.
I hope this helps.
Sorry for the long post