I tried using my Elec fillet knife. I'm embarrassed to show the results I got!
My gosh, you do a heck of a job! If you ever make a YouTube video on your technique, please share the link here..

12 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (decreasing), SMB, and HSB (only two have been seen in 5 yrs)
I think that's about all I should put in my little pond.
Otter attack in 2023.