The most common reason for foaming coolants is a lack of minerals in the water supply (also known as soft water). We suggest checking the hardness of your water using our Hardness Testing Sticks. This quick and easy monitoring step will prevent overflowing sumps and help to ensure that, without foam, any tramp oils will separate more quickly on the surface for removal. The second reason for foaming coolant is over-aeration. This can be caused by high pressure delivery systems and/or piping routes (never use a 90° angle) as well as aerating devices, such as our Oxygenator (whenever your machine pump is running, you can unplug it without negative sump effects).