Okay, so from what I'm reading here and elsewhere, floating plants are the best option.
To answer gr8nguyn1, green water is caused by too high light + ammonia among other things.
Mudboots, I'm going to use floating plants to combat this. It's been going on for over a month and now humbletex's tank is doing the same thing. Neither of us have floaters right now. Between you and me

I"d recommend something that won't get eaten by the average fish, such as Red Root Floater or Salvinia. Maybe Lemna major? The mollies that Dustin and Rita have ate all the Mosquito Fern and Lemna minor. What do you think? Didn't you recently collect some floaters?
By the way, if you'll be in Bryan Saturday, I'll bring that light fixture for your 20 gal. And you can maybe bring me some floating plants for Rita.
Diana K, I think it was triggered by a sloppy job filling up the tank whenit was first set up a couple months ago, so organics got into the water column. The only thing that makes me suspicious as to whether that may or may not be true is that fact that I've been changing water heavily. So it seems like I would have cleared that up? I do have a very thin gravel layer compared to most NPT's.
-Dave