Accidentally got some algae in my "dry" start...how can I get rid of it?

[HybridHerp]

So, while I was away I had my neighbor mist my 5 gallon dry start on HC
now, the plant has been growing and doing okay but when I came back I noticed that there was more water in the dry start than I would have liked, and that this had an algae film developing and a relatively good amount of algae in general.

The steps I have taken so far have been to add more water to the tank so that I could scoop some algae out, then drain it back down so that there are no submersed spots in the dry start.