Typically if putting a lot in, if available in your area a spreader truck is called, it backs up to the pond in as many places as possible and it slings it into the pond. With your pond, spreading it out by hand may be labor intensive, but it might be the best way to do 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).