Thanks, Tilop. I do plan on draining and re-sculpting in the future. Now, I am in Houston; the pond in Mississippi. 3 or 4 yrs away from full time management. The pond is overaflowing from all the rain so will pump off a ft. or so off the bottom; have some more sweet gum and tallow saplings in shallows to bring down. Does enough aerobic bacteria not occur naturally? If not, what do you suggest; how much for 4 to 500,000 gal. pond, and what specific bacteria to look for? Again, thanks for input>