FWIW, most aquaculturists only let their zooplankton mature in a new pond for a few days to a few weeks, depending on the size of fish they plan on stocking.
I've also heard of an interesting theory that if you have a neighbor with a pond that you particularly admire for it's water quality that you should innoculate your pond with a five gallon bucket from the other pond.
Funny how the little buggers are so ubiquitous that they just "show up".
