Just a couple things I figured I'd butt in on. You can use red wine vinegar to test your rocks; I tested mine with rice wine vinegar because I don't keep the white kind around. It just needs to be acidic, that's all. If your rock fizzes like pop/soda, I wouldn't use it in your aquarium. Just make sure to rinse the rock well after the test to get any remaining vinegar off.
I have a Perfecto Fluorescent light on my aquarium, which is is a little bigger than yours. If it's the stock bulb it came with, you likely won't have any luck with anything other than java moss. Java fern MIGHT make it, but it's doubtful. After some digging, I found out that my 24" bulb produces a measly 20W, and it's brand new.
Hope that helps!