Sad azolla?

My superpower is killing plants.  I have a month old well water filled epdm lined pond; 10 by 5 ft by about 2.5 ft at deepest point in zone 5 and it gets full sun throughout the day. Air temps here have been ranging in 40s-70 F for past week or so. This week I added about half a gallon bag full of azolla (from Arizona)  and it mostly turned brown and appears to have died with only a few stray green spots left. At the same time I added some hornwort and bacopa, garden soil does run off into the pond at times but otherwise nothing else added.  I'm not sure if I just shocked it or did something else to cause it to decide it didn't want to live in Michigan, does anyone have any experience with azolla/any ideas ?

wiki page on azolla

Azolla cannot survive winters with prolonged freezing, so is often grown as an ornamental plant at high latitudes where it cannot establish itself firmly enough to become a weed. It is not tolerant of salinity; normal plants can't survive in greater than 1-1.6‰, and even conditioned organisms die in over 5.5‰ salinity.[17]

If there's a phosphorus deficit, azolla goes purple, sometimes even reddish brown. Can you confirm that this is a true dead brown and not a purple shade?

Phil Stevens wrote:If there's a phosphorus deficit, azolla goes purple, sometimes even reddish brown. Can you confirm that this is a true dead brown and not a purple shade?

This was it! Added a little turkey manure, azolla is looking like it will survive me. Thank you for the help!