Silt. Soft, gooey, mucky black pond bottom stuff oozing between toes, staining shoes past ankles. Decaying organic contents of silt smell like rotten eggs. Nature gives us silt, naturally. Fallen leaves, grass clipping, runoff and fish stuff become ingredients of silt on pond bottom.
Ponds eventually collect enough organic matter on the bottom that they lose depth. Shallower ponds mean more light reaches the bottom to grow algae and weeds. Noxious odors are given off by anaerobic bacteria in the muck.
Supplementation with natural bacteria can dramatically reduce silt and muck, reversing the aging process and restoring depth.
