I do occasionally have filamentous algae in the pond. I recently had a pretty bad bloom that cleared up with a little Cutrine Plus.
I'll try to post some photos as soon as the weather cooperates. The film is not evident during or immediately after receiving rain and we'll probably be getting rain through Wednesday.
The fact that it disappears during rain and takes a little while to return even after the rain stops probably confirms CJBS2003's point that aeration would help...
