Well, one year later and the pond is still grey and visibility remains around 20" or so. After reading through a few more of these threads, it seems like it may be the bullheads that are causing my problems.

Any other thoughts on how to verify and cure the issue?

1 Acre Pond with SMB, YP, LMB, GSF, RES, FHM, GSH, Papershell Crayfish, Pike
5.5 Acre Pond with LMB, BG

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