You can't add a small amount each week and wait to see results. You've got to add enough all at once to get the concentration up to the recommended PPB at once and keep it there for the recommended 30-45 days.

How much did you buy, and what type of Fluridone product is it?

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).