Your problem plant is water shield technically called Brasenia schreberi. Normally this grows mostly in shallower water down to around 6 ft deep unless the water is very clear. With real clear water it can grow to depths where light penetrates - maybe deep 12-16ft?. The leaves and stems usually have a somewhat thick gelatinous coating that resists penetration of herbicides. Aa added surfactant would be needed to get good penetration of the herbicide. It might take a special aquatic herbicide to get a good kill. Do plenty of homework before and label reading before trying to kill it. Manually a tool called a Weed Razor would cut it well for removal instead of chemicals.
I think there has been good discussion here on the PB forum for what herbicide works well for water shield. Do a search in Google for Pond Boss Forum control of water shield.

Here one of the past good info posts for watershield
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=543773#Post543773

Last edited by Bill Cody; 10/04/24 08:57 PM.
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