You've got some good advice so far. The one thing with planted tanks though, you can do a nice low light tank with a stock setup or you can drop thousands of dollars (literally) into a planted tank.
The first place I would start off would be lighting. You said you have a 4 bulb T5HO fixture, any idea the watts and kelvin rating of the bulbs? T5HO's are a whole different animal when it comes to the WPG
rule so figuring out exactly what you have will help in the long run. You want a kelvin rating around 6700k (full daylight).
Once you figure out how many watts you have over your tank you can then decide if you need CO2
, ferts and what not. Basically, anything over 2.5wpg you will need CO2
to help combat algae.
With that being said, you can have a low light/low maintenance tank that runs on 1wpg. You can get by with swords, ferns, moss, crypts, etc. You can have a nice looking tank with little to no effort on your part.
The opposite end, which I did for a while, is a high tech/ high light tank. I had 3.5wpg over my 30g tank and had to do weekly trimmings of my stems. I had auto dosers that would dose premixed fertilizers in everyday and a pressurized CO2
tank. I easily dropped $400+ in that setup between tank, lights, co2
tank, ferts, dosers, pumps, reactors, etc.
I think you really need to decide how serious you want to take this. If I were you I would just set up a regular tank and just try throwing some low light plants in. You can use cheap playsand ($4/50lb) as a substrate and have a high tech tank. Substrates are a bit overrated, and over priced, in my experience.