After having a few barrels leak (white ones, not the blue ones). I'd just google dockbuilders supply and get the floats shipped to you if you are going the floating dock route. Less hassle to build using the floats vs. barrels.

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).