Mud on New Pond Liner: Montmorillonite Clay vs. Plain Dirt

Plain Dirt Is Not Beneficial

Mud on the liner clouds water, harbors anaerobic bacteria, and makes cleaning harder. It does not provide minerals.

Montmorillonite Clay

This specific clay (kentonite) adds trace minerals and can enhance koi color, but it's a supplement—not a liner underlayment.

Fix

1. Siphon off loose mud.
2. Cap planting pots with 1–2 inches pea gravel.
3. Add a bottom drain or regular vacuuming schedule.