Welcome to PB!
Is there ANY doubt concerning the ID? Wow, 10' stands of chara are unheard of down here. High-alkaline water? Just wondered.
If indeed chara, it is a tough call due to the variables that are present. But, I'd suggest looking into CUTRINE PLUS GRANULAR, applied on sunny days - and target two or three high-use sites at a time (vs the entire pond in one treatment). Treating too much area at once might pose fish-issues. Treating areas that are too small could be a futile effort and waste of time/$ due to rapid diffusion of the copper.


Kelly Duffie
Cypress, TX