Again, different weed species respond differently to different herbicides including the granular products. What is the weed species or post a picture of it. Are you sure it is not Chara or Nitella? For these see this both appear fairly similar.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=292990#Post292990
Is the water clear?


Last edited by Bill Cody; 05/22/12 10:21 AM.

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