Over time, E-Coaters will gradually increase voltage settings on the rectifier to maintain the required film build. This gradual increase in the rectifier voltage compensates for the gradual increase in the resistance of the Membrane. At times, conditions arise where an increase in the voltage setting on the rectifier will not correct low film builds. This could be due to a number of factors, including the age of the Membrane Shells. For more information regarding voltage conditions, see Service Reference HERE