I'm a belt and suspenders type of guy when it comes to ponds. If I'm going to the expense and hassle of re-digging the overflow pipe, I would use multiple methods. Sure it will be more expensive than only one method. But what would it cost to dig it up again?

Also, remember that it's not only the anti-seep collar, it's how the dirt is placed back around the overflow pipe as SetterGuy has found out.....

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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).