I have a 20 gal, also.
I bought 2 bags of seachem fluorite, the.. 20-something lb bags, i believe. it was more than enough.
I also have a 150-watt jager heater. So that I can easily have my tank go to near-90 in case of an ich epidemic (which I am currently suffering from right now).
Just in case you don't have it, I also have a aquaclear 50/200 so that my tank can approximately turn over the water 200 times in an hour.
I also have a 36 watt cfl. I think that's about it when it comes to my tech.
Good luck finding the right products for yourself.
All I know is plan, wait, don't settle for less. save. wait as long as you have to, but just get the right thing the first time. you'll end up spending less, and being satisfied for longer.
my caveat to you: don't buy fish that are too big for your tank, if you do not already have a tank ready for them to move into (like the 60 gal that you have no room for). I advise you to stick with something small, get the hang of the aquarium game, and then get a monster tank for your many cichlids to thrive
