Lake Kanasatka, in Moultonborough, has had a serious issues with phosphorous loading and the resulting cyanobacteria blooms for several years. In 2023, for example, a cyanobacteria warning was issued by the state that lasted from late summer through the fall, 121 days in total.
The following articles detail the issues facing that lake and the costly solution to solution to that problem. (Ed Note: Even with this treatment, Kanasatka continued to have cyanobacteria blooms last year, although with a much diminished duration.)
Restoring Lake Kanasatka FAQ Bulletin
Alum Treatment on Lake Kanasatka has successfully eliminated Cyanobacteria Blooms
Lake Kanasatka Feted for Reversing Cyanobacteria