Got it. I sprayed about ,2 ac. Mixed it at just under the 10:1 ratio you suggested. 4 10ths of a gallon into the 4 gallon sprayer.
Unfortunately no wind this morning, so no spraying. I’ll be down at the pond in an hour or so, and see if my spraying did anything.
Thx

9 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (going away), SMB, and HSB (only one seen in 5 yrs) Restocked HSB (2020) Have seen one of these.
I think that's about all I should put in my little pond.
Otter attack in 2023