A $5 million alum application on Grand Lake is underway. A barge carrying aluminum sulfate, which deactivates phosphorous, the lake algae's main food source, and a buffering agent that keeps pH levels from fluctuating skims across the lake on Monday. The treatment is expected to take about 30 days to complete, state officials said. Local officials hope the treatment will result in no water advisories for the lake this year and give tourism a boost.