Ultrasonic Cleaner Solution: Types, What Each Removes and What to Avoid

This page describes products and general use; it is not medical advice.

An ultrasonic cleaner solution is the liquid, usually water with a cleaning agent added, that fills the tank of an ultrasonic cleaner. The choice of solution decides which soils the cleaner can remove, how strongly the tank cavitates, and, for instruments used in healthcare, whether the bath itself becomes a source of contamination. This page is for clinic staff, lab technicians and buyers who need to know what the main solution types are, what each is documented to remove, and what to keep out of the tank. For how the machine works, see how an ultrasonic cleaner works.

What goes in the tank

Ultrasonic cleaning removes soil by cavitation and implosion: sound waves in the liquid form tiny bubbles that collapse against the surface of the item (CDC, checked 2026-10-30). The liquid is normally water-based. One manufacturer describes the process as using “a tank full of water-based cleaning solution” (Safetykleen International, checked 2026-10-30), and different contaminants call for different chemical formulations. A solution is therefore chosen for the soil, not for the machine.

Types of ultrasonic cleaner solution

Solution type	What the source says it is used for	Source
Alkaline detergent	Removing machining oils, lubricants, carbon, and carbon	Ultrasonic Power Corporation
Phosphoric-based detergent	Removing rust, calcium, minerals, lime and oxidation	Ultrasonic Power Corporation
Neutral or near-neutral pH detergent	Commonly used for cleaning in healthcare facilities	CDC
Enzymatic cleaner	Protein-containing soil; not a disinfectant, must be rinsed off, may cause allergic effects in users	CDC
Water with a cleaning agent matched to the soil	Three chemistries are named for industrial parts: carbon, rust and scale, and grease	Safetykleen International

Ultrasonic Power Corporation notes that each detergent it supplies has its own mixing rate and temperature range; follow the directions for the product you use. For enzyme solutions, the CDC says to follow the manufacturer’s instructions for dilution and contact time. Enzymatic products are covered in more detail in what an enzymatic cleaner is.

Why a surfactant matters, and why foam control does too

Pure water cavitates less readily than water with a surfactant, because its surface tension is higher. Ultrasonic Power Corporation states that a surfactant lowers the surface tension of the liquid, which lowers the cavitation threshold, and that adding one dramatically enhances cavitation activity. The reverse also holds: the same source says de-foaming agents significantly reduce cavitation activity, and it advises against detergents made for spray washers, which often contain de-foamers.

The practical reading is that the solution is part of the cleaning mechanism. A product built for a different washing method can quietly weaken the effect the tank is supposed to produce.

Water choice and temperature

For industrial parts, Safetykleen International says that distilled or deionised water with the right cleaning solution improves efficiency and prevents mineral buildup. It also states that heating the solution to 40-60°C improves cavitation efficiency. Both are vendor statements about industrial cleaning, not a rule for every item or every machine; the detergent maker’s directions govern.

Healthcare instruments: what the CDC says

The CDC Guideline for Disinfection and Sterilization in Healthcare Facilities (2008; web page dated 28 November 2023, checked 2026-10-30) makes several points that matter for the solution:

• A neutral or near-neutral pH detergent solution is commonly used.
• Bacterial contamination can be present in used ultrasonic cleaning solutions, and the cleaning fluid could result in endotoxin contamination of surgical instruments.
• Ultrasound alone does not reliably kill bacteria. It can boost the effect of a disinfectant when the two are combined.
• Enzymatic cleaners are not disinfectants, and the proteinaceous enzymes can be inactivated by germicides.
• Detergent enzymes can cause asthma or other allergic effects in users, and enzymes must be rinsed from the equipment.
• All instruments should be individually inspected and be visibly clean.

For where cleaning sits relative to disinfection, see high-level disinfection and the Spaulding classification and medical device reprocessing. Endotoxin as a measured quantity is covered in LAL endotoxin testing.

What to keep out of the tank

• Flammable liquids. Safetykleen International advises avoiding them, along with parts with loose coatings and fragile plastic components that can warp.
• Spray-washer detergents. They often contain de-foamers that suppress cavitation (Ultrasonic Power Corporation).

Common mistakes

• Treating the cleaning bath as a disinfectant. The CDC states ultrasound alone does not reliably kill bacteria and that enzymatic cleaners are not disinfectants.
• Leaving used solution in service without regard to contamination. The CDC notes that used solutions can carry bacteria and endotoxin.
• Skipping the rinse after an enzyme solution (CDC).
• Using a detergent outside the mixing rate and temperature range its maker gives.
• Choosing a solution without matching it to the soil: oils and grease, rust and scale, and protein are handled by different chemistries.

FAQ

Can I use plain water in an ultrasonic cleaner?

Water is the base of the solution, but pure water cavitates less readily than water with a surfactant because of its higher surface tension (Ultrasonic Power Corporation). The cleaning agent is what is matched to the soil.

Is ultrasonic cleaner solution a disinfectant?

Not by itself. The CDC says ultrasound alone does not reliably kill bacteria and that enzymatic cleaners are not disinfectants. Combining ultrasound with a disinfectant can boost the disinfectant’s effect.

Why not use a spray-washer detergent?

Those detergents often contain de-foaming agents, which significantly reduce cavitation activity (Ultrasonic Power Corporation).

Which solution type suits rust or scale?

Ultrasonic Power Corporation names phosphoric-based detergent for removing rust, calcium, minerals, lime and oxidation.

Sources

• CDC, Guideline for Disinfection and Sterilization in Healthcare Facilities (2008), cleaning; page dated 28 November 2023, checked 2026-10-30.
• Ultrasonic Power Corporation, Chemistry for a successful ultrasonic cleaning; checked 2026-10-30.
• Safetykleen International, Cavitation and ultrasonic cleaners; checked 2026-10-30.