hey, a couple things. about the bulb situation, it really depends on what type of plants you want to keep in there. if you want to stick with the moss ball and other moderate and/or high light plants, your lighting will need a pretty big upgrade. either retro-fit your fluorescent fixture to accommodate CFLs or buy a new fixture (an incandescent one would work, then you could screw in some CFLs). or if you'd like to go with low light plants only, all you really need is a new bulb. assuming you have an 18" bulb, this would work -> Fluorescent Aquarium Lighting: Zoo Med Ultra Sun Trichromatic Fluorescent Bulbs
or you can go to walmart or a hardware store and get one. i picked up a GE brand one at walmart for 6 bucks. just make sure that the color scale is somewhere between 6000 and 7000k and you'll be good to go.
also, if you haven't already checked out this thread, check it out Fishless Cycling For Dummies
for your new 20 gallon tank. and if you don't already have one, you're definitely going to want to pick up an API Freshwater Master test kit (or similar liquid reagent test kit) for your cycle, and to watch the levels on your existing tank (if you don't already do so).
your stock seems good, except i see in your post you mentioned a loach but not in your "my tanks" in your profile, if you do have one, what kind is it?
i like your tank, i would move the thermometer to the side, tho
do the large rocks collect a lot of detrius and gunk? i mean, it looks pretty clean, but is it hard to get clean? the large rocks look really cool, much different from the norm pebble gravel or sand. nice job
and i hope you're able to bring your moss ball back to life, they are very cool, i really want one when i'm able to get higher lighting