Very nice. I may try this. A few additional questions:
1. What are the odds of cultivating organisms that EAT or are harmful to the aquatics if the water is from a pond that doesn't have aquatics growing in it? Have you run into this problem before?
2. Are daphnia visible to the naked eye? I ask because in my first (and failed) attempt with Aldrovanda, I attempted to grow it in water collected from a local pond. It wasn't the pond water per se that led to their demise, but a water mold problem to due negligence on my part (not enough water circulation). In any case, within a week of setup, there were large colonies growing 1-2" below the water surface consisting of very small, barely visible whitish organisms that were self-motile. I know very little about aquatic biology and don't have a microscope at home, so I wasn't able to ID them. Perhaps these were daphnia?
My main concern is with regard to question 1. If plain-old pondwater is unlikely to contain bugs that are a serious threat to my plants, then there's no need for question 2 (isolation).
Again, thanks for the good tips and link.