I prefer to use aluminum sulfate along with hydrated lime as a buffering agent.

If it's clay, then it is staying suspended in the water by the ionic inbalance in the water between the clay and the water.

Here is some reading material for you:
https://www.pondboss.com/news/inside-pond-boss/clearing-muddy-water

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=283542#Post283542

and

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=283542#Post283542

www.hoosierpondpros.com


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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).