In reaction simulations with ISAT it has been proven beneficial in terms of efficiency and stability to clear the ISAT table periodically. You can clear the ISAT table either manually in the “Integration Parameters” Panel or by means of an Calculation Activity. The calculation Activity must contain the following TUI command: /define/models/species clear-isat-table By means of the Calculation Activity the ISAT Table can be cleared automatically at a specified interval (every n iterations).