Workers with Celina Tent on Monday prepare curtains that will section off an 8.75-acre test area of Grand Lake at the West Bank boat ramp where alum will be added to the water. The state hopes alum will be an effective chemical to inactivate phosphorus in the water that feeds the lake's toxic blue-green algae. Other test sites where alum will be applied include Harmon's channel (13.1 acres), 4-H Camp (10.18 acres), Otterbein channel No. 1 (7.55 acres) and Otterbein channel No. 2 (5.25 acres). The west beach (8.11 acres), will receive no alum, but will be used as a control site. Alum application is expected to start Thursday and be completed Friday at all six sites.