From an editorial published in the Toledo Blade:
"Western Lake Erie is too big to correct its noxious algae problem with large doses of aluminum sulfate, or alum, alone. Still, alum treatments appear to be having at least a limited positive effect on Grand Lake St. Marys.
At 12,500 acres, Grand Lake St. Marys is the largest open body of water in Ohio. Like Lake Erie, its recreational activities are afflicted by algae.
The state of Ohio has spent $8.5 million to apply alum to 4,900 acres of Grand Lake St. Marys over the past two summers. The compound is supposed to keep algae from feeding on its main food source, phosphorus.
This year’s drought cut off the farm runoff that feeds Lake Erie algae. But algae in Grand Lake St. Marys rely more heavily on phosphorus embedded in lake sediment, so this year’s dry conditions did not do as much to curb algae there.
Preliminary alum results for Grand Lake St. Marys look good, according to a researcher. But the success needs to be quantified for state officials to decide whether to apply more."