2. The high-frequency ultrasonic waves are carried to the unit through a cleaning solution. That liquid-based medium can be one recommended and sold by Sharpertek, or a combination of common tap water and soaps and/or degreaser chemicals compatible with the component being cleaned. For proper operation, the Sharpertek tank is filled until the liquid level reaches about one inch from the top. The SH500-20L displaces 20 liters (or 5.3 gallons).