Seems to fit the original ID description of chara. I wouldn't worry much about it - as your pond ages and nutrients build up macrophytes will appear. Chara is a far better option than many others...I recommend keeping an eye out it responds pretty quickly to algaecides per your experience. Keep growing those brute CNBG!

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

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