I would be very careful at eliminating a pond full of weeds (80%-90% coverage) in the warm water of summer. A massive weed kill will cause a strong reduction of dissolved oxygen which may result in a fish kill. Several factors such as temperature, amount of sunshine, amount of phytoplankton, presence of lake dyes and average pond depth will come into play here.


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