Drill some 1/4" or so holes in the bottom of a 5 gal bucket. Pack 6" in the bottom. Fill with water. See if it leaks out....

If it does leak, and you used dry clay, try adjusting the moisture content before packing and see if that solves the leakage problem.

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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).