I cannot very well see the needed structures for identification of Chara nor Niaid. From a far distance it looks more like Chara than Niaid. Try to get some close up pictures of 2 to 4 stems of it laying in 1/2" of water in a shallow disk or pan. If you used the correct concentration of Diquat it should have killed most all the Niaid. Using Cutrine/Diquat too early in the season's low water temp could have minimized the effectiveness. Water temp should have been in high 60s - 70F.


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