The State of Ohio is considering dumping alum, or aluminum sulphate, into Grand Lake St. Marys to zap the phosphorous that helps fuel blue-green algal blooms.
The alum dump carries its own risks, but has been used to successfully treat over 300 lakes. The state might test the strategy over a 40 acre area of the lake to determine whether it will be effective; and if it is used lakewide Grand Lake St. Marys would be the largest lake to ever receive an alum dump.
The full dump is estimated to cost between $7 to $10 million, as reported by the Columbus Dispatch.