I have digged a rather large pond (about 10x10 meter and 1.5 deep). I want to seal it but in a natural way. So no plastic or concrete. I was looking into Sodium bentonite (I was reading about that) but I only can get it with Polymer mixed in it. That doesn't sound natural to me. Any other suggestions? I am living in Thailand (in the north) and the soil is kind of an orange silt type of soil.
Kind regards,
Peter
