The alum treatment of the East Arm should be ending this afternoon. One development we are seeing is that the Alum floc is grabbing algae cells and forming a surface scum in some areas. This condition should be very short lived and these should sink as the day goes on. We will be keeping an eye on this. Alum captures materials in the water that have a negative charge such as phosphorus, algae cells are also in this category and if a substantial number of the bonding sites grab algae cells that are buoyant it can cause this condition.