From lookin at ALL of your questions, it seems like you need to go high tech, it's what you are trying to do, except it doesn't seem like you want to commit to the trouble yet.
High tech is trouble. It takes time, money, and patience. There is a large investment up front. Going high tech means adding co2, ferts, and lighthing. If you are going to add one of those, sooner than later you have to add the other two. There is no easy way.
For your lighting, the 55g hex is tricky. I'm pretty sure to get the watts you need, your only option is a diy hood. I've seen plans around for a hex hood, you'd just have to modify it for your dimensions. This will cost money and it will take time to build. If you want co2 and ferts, you have to do this.
CO2: You can use DIY. You will have lower levels than people using pressurized. You'll have to commit to exchanging the culture every 12-16 days. This is time and patience. Little money.
You can also go pressurized. This means taking the tank in for a refill every 6 months. This is no time, no patience, but money.
If you want ferts and lighting, you have to do this.
Ferts: There is no "A to Z" fertilzer as you have asked. You can buy the whole line up of Flourish products and go from there. This means a little time, some patience, a lot of money. You can also read
www.rexgrigg.com about dosing fertilizers(in fact, while you are there, read the whole site). You can then purchase fertilizers from him. This means some time, some patience, little money. If you want co2 and lighthing, you have to do this.
The results will be vibrant colors in your plants and extremely fast growth. This means pruning, often. This is time and patience, no money(well, it can mean money in the "plus" column
).
Adding any of these things without adding all of them will result in an imbalance. You will either be wasting money(adding co2 w/o lighting) or causing a really bad algae bloom(ferts and lighthing w/o co2). Heck you can even cause algae by not adding ferts(lighting + co2, no ferts, imbalance, BBA, bad stuff).
You can also go low tech. No co2, low lighthing, no ferts. If you select the right plants, you can have a heavily planted, beautiful aquarium. This means little time, some patience, and little money.
