The memory usage shown in the Geneious Memory Usage bar will creep up and occasionally drop down automatically as JAVA memory management reclaims previously used memory. You can force Geneious to free up unused memory by clicking on the Memory Usage bar - this will force a "garbage collection" and after a second or two you should see the memory usage drop down. Note that the Memory Usage bar is hidden by default. You can activate it under Tools -> Preferences -> Appearance and Behavior. If the indexer is running this will also use memory - see “Why is my indexer continually running?” in the Geneious Databases section.