Pond Boss Forums GENERAL QUESTIONS Help Pond Maintenance Help?

You may have expectations and goals set too high for a dirt bottom pond.
Rainman is correct "Dirt is full of nutrients". These nutrients are feeding the algae which are plants. 0.66 ac is a relatively large swimming pond. Ponds are catchment basins and GREAT nutrient collectors by trapping all sorts of organic materials that contain nutrients to add to your already nutrient base when these organics biologically decompose and recycle the bound materials. You will fight algae and other plants as long as you own that pond. Generally, the ponds tends to grow more plants over time due to pond aging and natural eutrophication.

I would check the swimming pond websites and learn what other pond owners are doing to deal with nutrient accumulation and continual plant growth.