Ken, I'm going to add on to this thread because of my duckweed situation this year. I'm a little puzzled by it. We've fought FA every season for the first three years on our pond. But this year (finally) not much FA! We are super happy! But....now we've got a huge growth of duckweed occurring. I don't like either one very much, but it's maybe a bit easier to fish through the duckweed. And the wind moves it around better. Just odd to have so much this year. We've had aeration in since spring 2016. Our bottom condition gets better/firmer all the time. We've repaired both the inlet silt pond dams, so are getting less and less direct run in of nutrients. AND, I raised the pond by ~ 24 inches this year, so we have deeper edges with less light penetration to the bottom (e.g. less fuel for the FA). The only additional 'change' from last season was that my pond was drawn down 3 feet for 3 months this winter (for the outlet pipe modification). This meant hard freeze of the edges of the pond that were newly exposed to the air. We've been thinking this was good for FA control. Would it somehow help the duckweed? We got some big rains mid winter and this spring and have been full pool + the new 2 feet all this year.
My current speculation is the duckweed is utilizing my nutrient load that the FA used to. If the FA is not around to use it, 'somebody will' I suppose. I am hoping more emergent plants will show up to take up some of the load. My attempt at starting eel grass was not successful. I remain leary of adding a plant that may become a nuisance.

"He who thinks he can and he thinks he can't, they're both usually right." - Wyatt Hendrickson, 2025 NCAA Hwt Champion