Reward (diquat) breaksdown or decomposes rapidly in a pond not much active material left after 10days to 2wks, sometimes even more rapidly. It has not copper. Copper products are primarily for algae problems you have a vascular plant problem - (macrophyte - leaves stems roots). If you treat promptly water will be okay for trout in 2 weeks unless there is lots and lots of dead plant biomass consuming oxygen as it decays.


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