Hi DBR:
Ever consider Harvesting? With so much plant material, harvesting may be your best bet. Killing it and having that much biomass floating to the bottom of the lake can't be good.
I just saw a presentation of that too at Michigan Lakes & Streams Assn., some went from chemicals to harvesting, depending on the plant problem and size of their lake.
Rule/permits are different in every state.
Lynda

HUSBAND AND CAT MISSING -$100 REWARD FOR THE CAT!
I subscribe too, but tried and failed at the fish logo.