You are better off using a low dose of Fluridone. 10 PPB dosage will kill it and not kill other plants in the pond. You cannot have water flow thru for 30 days though.
I also have curlyleaf pondweed and naiads that I would like to control with Fluridone. I have some pickerelweed that I purchased and planted and don't want to harm. This label indicates that pickerelweed is
not controlled by Fluridone. Not sure if that means zero harm but sounds promising. Also, the standard dosage on that label in 90 ppb. Is 10 ppb Fluridone safe for pickerelweed in your experience? I think so.
https://www.solutionsstores.com/amfile/file/download/file/1779/product/618/
