Stuff growing on plants

[llama0788]

I got a 20g tank off of Craigslist almost 2 weeks ago at this point. When I got it, there was a serious green water problem that I cleared up with some partial water changes daily. But now there is some sort of algae that is still on the dwarf hairgrass. Any ideas as to what it is and how to get rid of it?

I have an Aquaclear 50 and 96w power compact as far as tank specs go, and using a CO2 liquid supplement.

Thanks!