The initial alum treatment has been applied to Grand Lake St. Marys with positive results. Highlights of the treatment include:
- Alum (aluminum sulfate) binds with phosphorous and causes it to sink to the lake bottom, thus starving blue-green algae of its food source.
- Five sites were scheduled to receive the treatment, but two were scrapped due to shallow water.
- It took approximately 90 minutes for the alum to bind with the phosphorous and sink to the bottom. Water clarity improved, in some areas to a depth of 4.5 feet.
- Water at each site will be tested over the next 60 days to determine how effective the treatment is in reducing blue-green algae.
- If the treatment is deemed a success, a whole-lake application could be scheduled at an estimated cost of $10 million.