Image of How pH Strips Control the Chemical State of Your Coolant

How pH Strips Control the Chemical State of Your Coolant

pH Strips Monitor Coolant Chemical Condition

pH strips are used to test the acidity or alkalinity of water. They are also used to determine the pH level of the coolant in your machine.

What do pH strips test for:

Getting more technical, the strip measures the hydrogen ion concentration (pH) of a liquid by measuring its electrical potential. It uses a colorimetric indicator that changes color when exposed to different levels of hydrogen ions. Therefore, the color of the strip will change depending on the acidity of your coolant.

Are pH test strips accurate:

To test the pH level of your coolant, strips are one of the easiest products to use for your shop or facility. Simply place the tip into the coolant. Then, read the results by matching the color to the side of your container.

Each coolant has its own chemical range, but all are between 8-10 pH. By monitoring each sump at least weekly, you can address other maintenance issues. If your reading is below 7.0, then there is too much acid in the coolant. If the reading is above 10, then there is too little acid in the coolant, and the coolant needs to be adjusted.

It literally is as simple as that!

Why rely on your coolant guy to keep your metalworking fluid in its top chemical condition when it is so easy to do yourself, and prevent coolant problems?

Where do I get pH test strips?

Zebra Skimmers has pH test strips for your coolant monitoring needs.

  • Dip into fluid and compare your color reading to pH value color chart
  • Results in less than a minute
  • Range of 6.5-10.0 (for coolant)
  • Accuracy ± 0.2 pH (for coolant)
  • 100 sticks per package

Problems Related to pH

Coolants are designed to be alkaline, to neutralize the acidic emissions of bacteria which enter the fluid pool via the water supply, work material, our skin, and a host of other sources.

Reduction of bacterial growth can be achieved by removing tramp oil, aerating the fluid, and filtering particles. When these protocols are not in place, coolant failures can occur.

Q. Why is it important to check the pH of my coolant (and what is pH anyway)?

A. In basic terms, pH is an indication of the acidity or alkalinity of a fluid.

Water has a pH of 7, which is neutral. An acidic fluid will range from 0-7 pH, and an alkaline fluid will have a range of 7-14 pH. pH levels in your coolant drop due to bacterial emissions. Because metalworking fluids have an operating range of 8-10 pH, even a .2 drop in pH level can cause a host of problems, ranging from rusty machines and parts to sump odor and skin irritations.

With consistent pH monitoring and bacterial control methods, these problems can be prevented.

Below are some more detailed descriptions of what to look out for when your pH balance is off:


Your sumps will emit foul odors, caused by sulfuric and hydrochloric acid emissions. One of our favorite and simple ways to take care of this problem (if it isn’t too bad) is to use specialized odor control tablets for metalworking fluids. You just drop one in your tank and the bacteria will fizzle away.


Bacterial growth encourages skin sensitivity as acids build up in the fluid pool. It is best to wear protective coverings but sometimes the coolant can still get on your skin and possibly cause irritation. Remember to wash your hands with soap and water after any interactions.


When pH level is too low, concentrate breaks from oil/water emulsion and floats on the fluid surface. It gets skimmed off like oil and can easily plug particle filters. An oil skimmer can take care of that for you (and we know just the place where you can buy the best oil skimmer for the job!)


If your coolant concentration is low, the machine is running on mostly water. This generally provides insufficient lubrication and causes broken or prematurely worn tooling. Monitoring all of your machines can be time consuming but guess who has the answer? Click here to find out!


Rust preventative may be required with your coolant since the natural lubricant of your metalworking fluid is no longer part of the fluid pool. Machine interiors may also become affected. All coolants have short-term RP properties; however, there is no “one product to solve all” that is specifically designed to target and prevent rust.

The important component to mitigating rust is maintaining proper concentration. For example, you could buy the best coolant on the market with RP properties, but if concentration is off or isn’t maintained for that application, you’ll still have rust formation. One of our favorites is Eastern Oil’s  ExcelCool® 466.


Corrosion can be caused by many things, but one of the most common causes is a low coolant pH level. You should check your coolant because it can become contaminated with chips, debris, or other materials that can cause damage to your tools and even your machine.

Overall, you need to regularly test your tanks and monitor the pH levels of your coolant. This will not only keep your machines happy but your machine operators as well.

If you have any questions about monitoring your metalworking fluids, feel free to reach out to our specialists at 888.249.4855. We are happy to help you!




About Zebra Skimmers:

Our mission has always been simple. It is to provide the metal working industry with the oil skimmers and metalworking fluid management systems they need to complete jobs quickly and efficiently. Innovative and affordable solutions have gained us many accolades. Our continued growth is due in no small part to our excellent customer service… Not to mention our satisfaction guarantees and the performance of our tools.

Among our diverse options of oil skimmers and metal working fluid management systems, you can expect to find: