Guck growing in paludarium - solutions?

[Epiphile]

Just as an example, here's a really outdated shot of my paludarium. Forgive the quality of the photos...

Since planting the aquatic area I haven't seen algae, and the Rotala/Hydrocotyle species, mosses and liverworts grow like weeds (I just cut about a pound of stems out of there for a trade the other day). Lighting is 65W power compact, and the tank is a 20 gallon. To be fair, I do get a bit of algae on the exposed wood well above the waterline, but it's not unpleasant to look at, really.