Anyone try maintaining a small "pond?" It's actually so small (about 5 - 6 square feet of surface area) that I wouldn't actually consider it a pond. Obviously, a filtration system and skimmer system would be way over kill for something like this. Any ideas for keeping the green algae out of this. Would a small "ecosystem" of a few small fish and some plants work with period addition of bacteria to outcompete the algae?