You can control the output up to a 100%. You can reduce the output of chlorine so that it does not over chlorinate and turn it up to maintain chlorine levels.
Unlike conventional chlorine additives that must be constantly replenished, the salt is recycled continuously to further reduce pool maintenance. Most generators keep the cells clean with automatic reverse cycling that prevents scale build up on the cell. Cleaning can also be accomplished manually with a diluted solution of acid in water.