Haha, I dont think so, get pressurized CO2, possibly even DIY though I would not reccomend it. And just cuz ur CO2 runs out doesn't mean your screwed. You can always go lower light. Yes if you had high light and difficult plants, if you removed CO2, you would have to reduce lighting and in turn those hard plants would probably die since they needed that high light to begin with, but otherwise if you just have some easy plants that aren't too demanding, you will be fine.
Now as for the other things...
2700k compact flourescent is pretty much no light. I have gone to ACE hardware and tested their 2700k and 3000k CFL bulbs. Pretty much 10 PAR 1 inch from the light, so they will offer little to nothing. Don't waste $$$ on energy. I found a 5000k there for my emersed bowl and it delivers about 300 umols PAR about 7 inches from the source so, that worked for me. See if you can find something similar. Testing was done with the SAPS Apogee sensor.
Dirt will not produce CO2, though i am not sure on this. I do not know the chemistry behind it but i think can say that it will not provide enough. If you are trying to go without CO2, go low tech, that means low light. Once you hit medium light, your will want CO2. CO2 on low tech is also great, it will only help.
Aquatic plants are also very unique in that they can absorb nutrients not only from the soil, but also from the water. Thats why we can grow stuff in inert substrates like cat litter, gravel, flourite, etc. I personally don't like dirt since its messy and leeches tannins for a while. I chose aquasoil since it provides nutrients, looks great, and is easy to plant into. But it is only a supplement for the main fertilizing in the water column. So if i ran out of nutrients for some reason, I still have a backup to last a bit longer. Some plants are more heavy root feeders though like echinodorus. HUGE root systems.
Last edited by puopg; 02-24-2013 at 06:15 PM.