Tom - don't exect anything green to live in your pond when using princep. Water from a princep pond can kill tomato plants one year after application. Princep will also kill most if not all phytoplankton in your pond, then the whole fish food chain at the lower levels crashes. Don't expect many small fish to survive when using princep.

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management