Have you removed all the soil that was exposed by drawing down the pond?

If you didn't, then the WM could come right back once it fills up.

I don't believe Rotenone will affect the Fluridone, but you need to keep the same volume of water (or less) in the pond for 45-90 days.

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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).