How often to change ultrasonic cleaning solution?

This will vary depending on the cleaning application and the frequency with which the bath is used. When cleaning medical instruments, it is recommended that new solution is added to the bath twice a day - based on an 8 hour day. I.e. once every 4 hours. Depending on the convenience and application, industrial ultrasonic tanks may require a fluid change more or less regularly. The cleaning results and fluid in the bath should be monitored for contamination after cleaning and judgement made by the operator on how often the fluid needs to be changed.