That's a great question and I've been dealing with it as well with some pretty good success this summer. I wrote thread about it:
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Main=44176&Number=576011#Post576011My questions would be, how is your pond fed? How much water flows through your pond, is there a source of nutrients from farming or a swamp? Is your pond surrounded by vegetation or is it a manicured lawn all around it?
Also check out this article:
https://www.mdpi.com/2504-3129/5/4/53Im not sure where you are located but do your weeds die off in the winter? If so that adds nutrients as well.
I guess in a nutshell you need something to use up the excess nutrients either before they hit your pond or once they hit your pond. Once in your pond theyll be used up by vegetation or potentially vegetation around your pond ie. trees and shore weeds/plants. There might be some denitrification and ammonia removal with the right type of aeration like cascade or water fountain potentially, check out the many studies online to see how waste water treatment plants deal with removing excess nutrients from effluent ponds.
Im pretty sure adding an area of weeds as a biofilter will be a good thing.
Cheers.
