Common misconception, it's not a liner, however, the cross-link polymer enters fissures and travels as far as the current can take it where it lodges and expands. This could many feet below the basin or sidewalls of the pond. Walking on my pond sides treated with Soilfloc has not impacted the seal to date - still holding tight.

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

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