Whats the KH reading of your water? I find that plant tanks are generally easier to take care of if your KH is 4 or more.
When I had my plant tank, I felt the most important need was to have my CO2 consistantly dissolved at about 15-25ppm. Any lower, and the affects could be seen within a couple of days. My plants would stop pearling, algae would start growing, etc. Even on my low light tank, I never stopped injecting CO2... the benefits outweighed the hassle of setting up a CO2 system.
As to getting a CO2 system, as much as it can cost, I'd say, save your time and get/build yourself a pressurized system. Its much easier to handle than bottles of yeast and sugar. In my world, the easier it is to handle, the longer I'm going to stick with it.
Dissolving wise, a more passive system like the one posted above will work for smaller tanks... but after some experimentation, I found that putting it on any tank larger than 20g (depending on surface agitation) was really pushing its outter boundaries. A better alternative would be a sort of active system of dissolving CO2. There are several ways of doing it. Many people inject CO2 into a canister filter because of its ease. Though there is a risk of air locking your filter if you inject too much CO2 at once.
Secondly, I felt that the most important thing was dosing enough KNO3 (in the form of stump remover) to get my nitrates up to a constant 5-10ppm. Everything else I dosed according to feel... a couple drops of phosphates (in the form of fleet enema
) once a week, a couple capful of flourish trace once or twice a week, and some a little a couple pinches of powered phosphate (in the form of phosphate water softener) once a week. Having a good substrate rich in nutrients was also essential IMO for the success of my plants. I used pure flourite mixed in with detritus from my cichlid tank and only vacuumed areas not occupied by plants. All of my rooted plants flourished, and a few actually sent stalks up through the water's surface and flowered all the time.
Good luck with your plant tank!
-Rich