Reading through this thread, you are running off in differing directions with all the options, without actually addressing the all-important issue of light.
But before I get into this, Fishnerd101, welcome to Tropical Fish Keeping forum.
In the initial post you mention upgrading to a dual-tube fixture; are we to understand from this that you now have something less, such as a single T8 48-inch tube? Or a fixture with 2 smaller tubes such as come with the designed hood? If either applies, i would definitely upgrade to a dual-tube (48-inch) T8. This is what i term moderate light, and you can grow a lot of plants well without CO2 and mega-fertilization. You can see photos of my tanks which use this under the "Aquariums" tab below my name on the left.
There are several well-made dual T8 fixtures in 4 feet, by All Glass Aquariums, Pennplax, and others; they are not all that expensive depending where you buy them, but you can also use your skills to make something.
To the microsword, this is not an easy plant. I have it in my 70g (with dual-T8 tubes) but it is struggling. I recall posts from other members with similar problems. But this is only one plant, there are dozens of options.
On the issue of liquid carbon, such as Excel or API's Carbon Boost, I cannot recommend these because of their chemical properties. The question on this products effect on bacteria arose in another thread and my research turned up the following:
API CO2 Booster is 1.6% glutaraldehyde (rest is water). Seachem's Excel is the same but a slightly higher percentage. This chemical is toxic. It is used to disinfect medical and dental instruments and as a chemical preservative. Considered a hazardous substance, skin irritant, toxic if inhaled, etc. You can read more here (which comes from a link on the API website): http://cms.marsfishcare.com/files/ms...ter_081810.pdf
It kills cells, and is used in products that attack viruses and bacteria. So, it may well affect bacteria in an aquarium. It will kill some aquarium plants, Vallisneria is one. I wouldn't use it.
Natural CO2 occurs from the respiration of fish, plants and bacteria, but mainly from the breakdown of waste organics in the substrate. In a normally-stocked tank there is more CO2 than many realize. If the goal is not to spend enormous amounts of money, and have more of a natural method planted tank, I would forget the CO2 in any form, upgrade the light, and select from the many plant options. Several are in our profiles, second tab from the left in the blue bar across the top of the page.
Fertilization of the other 16 nutrients is best done with a comprehensive liquid. There are two that are very good, Seachem's Flourish Comprehensive Supplement
and Brightwell Aquatics' FlorinMulti
. A liquid will cover all plants, as they all assimilate nutrients from the water via roots and leaves, and the water makes it way into the substrate. Substrate fertilization with tabs can help some larger plants.