You will need to rent a rototiller to mix the bentonite with the soil, then use a hand tamper to compact as much of the soil as possible. Here you can also rent a small mechanical vibrating compactor that is about 1/2 meter square that is used to compact sand before placing bricks on top of it for a walkway.

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).