Errfoil, sorry for the mis-understanding. The Fluridone will NOT kill the Chara. I have never seen it work on Algae - Chara is a type of Algae.

I'd do a low dose treatment of CLPW in the Fall after this years seeds sprout, and plant beneficial native underwater vascular plants to re-populate the pond.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).